First Time To Bavaria...Logistics..Castles...

So you have 5 days from March 8 through March 12, and you have listed 9 places you would like to visit that are spread all over Southern Germany, I hope you realize you will not have time to visit all of them.

I didn't explain myself too well...
I meant since I only have 5 days after BMW tour, trying to figure out efficient way of experiencing as many of those castles / towns stated

I think you can do this castles & cars tour. Hang on to the car, that will speed things up.
3/3 Land and drive to Garmisch. It is generally not recommended to drive immediately after an overnight transatlantic flight, but my employer had me doing it all the time. You might be a bit worn out to do anything in the afternoon. see how you feel.
3/4 Neuschwanstein am, maybe that Zugspitze run in the afternoon.
3/5 Drive to Burghausen and see that. Then drive to Ingolstadt late afternoon/evening.
3/6 Audi Tour
3/7 drive to Munich and do the BMW tour, then drive west.
3/8 Liechtenstein Castle is closed in March. If you want to drive by and have a look, it is not too far from Hohenzollern Castle, which is open.
3/9 Drive to Heidelberg and see the castle. Burg Eltz is closed until April, so no use driving all the way up there.
3/10-3/12 Do your romantic Road trip heading back toward Munich.
3/13 Fly home.
Other interesting castles, Wartburg in Eisenach, Coburg in Coburg (only open 1-4 Tue to Sun), Haute Koenigsbourg in Selestat, France, just over the border closest to Hohenzollern.

"Thinking renting car and Zugspitze as an option for 1st day and spend night near Garmish (maybe have time to walk town here)"

Your first few days look messed up to me...

It's a sound piece of advice NOT to drive right after a red-eye international flight, when you may be jet-lagged/drowsy. I suggest that on 3/3 you just take the train to Füssen (€26/2 if your son is 15+, €20 if not, using a "Regio-ticket Werdenfels" ticket bought at the airport rail station.) Check in, shower up, rest if you need - then enjoy THAT small town first... visit the Hohes Schloss and have a walk through Füssen (it's quaint) using Earl Steinbicker's guide. That should help you deal with the jet lag and orient your inner clocks. It's not like you can drive right up to N'stein the next morning anyway - just leave your bags at the front desk of your hotel in the morning and take the bus from Füssen to the castle stop (only takes a few minutes) and pick up your car back in Füssen after seeing the castles-that-aren't-castles (N'stein is a palace built with a fake castle exterior just before the dawn of the 20th century.) You'll have time in the pm of 3/4 to drive to Garmisch for the night, but probably not enough time to visit the Zugspitze... I would just do the Bavarian evening in Garmisch at the Fraundorfer Inn on 3/4 and call it a day - then see the Zugspitze on 3/5. And visit Mittenwald as well - it's an outstanding little mountain town. But apparently you have to be in Ingolstadt on 3/6 at 11:00... that is really out of place... I mean, you COULD drive north to Ingolstadt on 3/5, but then you have backtrack to Munich on 3/7... any chance you can change that Ingolstadt appointment?? It would make more sense to spend 3/6 elsewhere and visit Ingolstadt AFTER your BMW date in Munich on 3/7 (then it's on your way north to Bamberg or wherever.)

if you decide to have a car the whole time, we did the BMW tour/BMW Welt ( wife and I enjoyed it very much), we had a car and found a hotel/apartment with good parking, within walking distance to the BMW complex and train station. that was an easy train trip into the centre of Munich.
good to see you have tour already booked.
hope this helps

Russ,
If I elect to take train to Fussen, how do I get around to Garmish, Zugspitze, Mittenwald,...Any bus tours?
There is a chance I could take the Audi tour on 3/8 instead... How would that change your recommendations..Thanks for help

"...how do I get around to Garmish, Zugspitze, Mittenwald,..."

My suggestion to you - since you want to do this by car - was to pick up the car in Füssen on Day 2 after you visit N'stein and H'schwangau.

leave your bags at the front desk of your hotel in the morning and take the bus from Füssen to the castle stop (only takes a few minutes) and pick up your car back in Füssen after seeing the castles-that-aren't-castles

I believe Autoeurope has a contracting agency in Füssen (and airport rentals sometimes cost more than town rentals, btw.)

That wouldn't be my choice - there's a bus + train connection out of Füssen via Reutte, Austria that takes you to Garmisch and Mittenwald on a scenic ride through Tyrolia - it's the Ausserfernbahn Railway (and of course the Zugspitzbahn is reachable fromG-P via free public transport - all guests in Garmisch can pick up a free visitors card for discounts and free local transport.) I enjoy train travel a lot more than driving and rental contracts and insurance - and dealing with sometimes-shady rental agencies.

"There is a chance I could take the Audi tour on 3/8 instead... How would that change your recommendations..."

3/8 in Ingolstadt would eliminate the backtracking that you have built into your schedule - don't you think?
So...

3/4: Overnight in Garmisch
3/5: Zugspitze, Mittenwald, other Garmisch-area pleasures... a 2nd night in Garmisch
3/6: Drive to Oberammergau, Landsberg am Lech (Romantic Road town,) maybe Augsburg, then Munich for the night
3/7: Do your morning BMW tour, see some Munich sights; leave for Ingolstadt in p.m.
3/8: Audi tour, then whatever to the north.

Russ,
Thank you for your time. Just trying to show my 14 yr old son the time of his life..
i am able to take Audi tour now Wed 3/8
can you look this over:
Fri 3/3:
-take train to Fussen and check in a hotel for 1 night
-visit Hohes Scloss and walk Fussen
Sat 3/4:
-leave bags at hotel in Fussen and take bus to Castle stop and tour N'stein/Hoh'gam castles
-take bus back to Fussen and grab bags
-take bus + train connection out of fusion Via Reutte (Ausserfernbahn Railway) going to Garmish...... this run in afternoon and how long trip?
-upon arrival Garmish check into Fraundorfer Inn (they are booked...any other suggestion?)for 2 nights
Sun 3/5:
-Train Garmish to Zugspitze in AM going to Summit in cable car
-Should I take cable car down to Eibsee and look around and Bus back to Garmish/Mittenwald/Lindholf?? trying make best use of time..
-i Probably need backup plan in case weather at Zugspitze bad (is there bus Garmish to Linderhof)
Monday 3/6:
You recommended driving Oberammergau/Landsberg am Lech/Augsburg which sounds good.....any way to enjoy these without car rental or just a one way one day car rental returning somewhere in Munich? Will not need car 7th/8th....I will plan on spending nights 3/7 and 3/8 in Munich (I guess best to find hotel near Munich Bahnhof) for BMW on 7th/Audi on 8th...

Thursday 3/9:
RENT CAR
check out Munich and start my 5 night travel loop thru following:
Munich-Burghausen Castle (possibly skip but don't want to)-Regensburg-Nuremberg-Bamberg-Iphofen-Wurzburg-Bad Mergentheim-**Rotenburg-Harburg
(i sure wish I could hit one of these 3 castles...Heidelberg/Hohenzollern/Lichtenstein castles but look too far out of way....old medieval castles fascinate me!)
-any input on which Locations to ditch completely and those which to concentrate more on....Really enjoy walking small quant towns. Would be nice to check into a hotel 2 times for two nights and the fifth night closer to Munich for flight out at 12:15 PM. Which towns would make good base?

Sat 3/4:

This info comes with the disclaimer that I'm no expert on the logistics of seeing both N'stein and H'schwangau in one visit. But assuming it's possible for you to be done and to be at the Hohenschwangau/N'stein bus stop by 14:43, you can catch the 14:44 bus 9651 to Füssen Bhf (station) (14:55.) Bus 4258 leaves Füssen station at 15:13 and arrives in Reutte at 15:40. The train to Garmisch leaves Reutte at 16:26 and arrives at 17:29.

OR: at 16:40, Bus 78 leaves the Hohenschwangau/N'stein bus stop for Füssen Bhf - then you do Bus 4258 from there to Reutte with a layover there for the train, which arrives in G-P at 19:29.

With either schedule, your bags will need to be left either... in a locker at Füssen Bhf... or at your hotel close to Füssen Bhf.
Note that for the 2nd later schedule above, there's an earlier 16:30 bus 73 from the Hohenschwangau/N'stein bus stop to Füssen Bhf (16:39.) This bus would give you 34 minutes rather than 24 to fetch your bags. This might be helpful if you choose to leave bags at your hotel.

Sun 3/5:

It's been a long while and I do not know the Zugspitzbahn or Eibsee details well enough to advise you for this day, especially in early March.

Mon 3/6

Oberammergau isn't hard on the way to Munich by train but Landsberg will be problematic to fit in using the train. If you aren't able to do Mittenwald on 3/5, you might do Mittenwald and Oberammergau this day. You can leave bags at Garmisch station while you see Mittenwald but not at O'gau station - no lockers. You can contact the O'gau TI office to see if they hold bags - my guess is that they will - they're open Mondays:
http://www.ammergauer-alpen.de/oberammergau/en/Contact-and-service/Contact-form-Oberammergau
If you only see Oberammergau on the way to Munich, I don't see having pm hours in Munich as a drawback. You're on quite the speedy treadmill as it is. I'm not so enthusiastic about going to Augsburg, really. I'd spend the night of 3/6 and 7 in Munich, probably. You may want to spend time in Ingolstadt after your tour there on the 8th. Or maybe you just stay overnight there instead of returning to Munich that night. You can likely rent a car in Ingolstadt just as easily as Munich.

I'll have to get back to you on your later plans later on.

thanks for seeing this thru

I was able to reserve a room at Fraundorfer for Sat 3/4 and Sun 3/5
I weather is Good 3/4 and can hit the Zugspitze and Mittenwald, then
It still is an option 3/5 to rent car one way into Garmish and hit Linderhf, then Ettal, Oberammergau (probably not Landsberg?) on way to Munich.
Still confused as to where to drop off car in Munich
We will definitely spend night Mon 3/6, Tue 3/7 (BMW+ Royal Residenz) Wed 3/8 (Deutches Museum+ Marienplatz), and just enjoy Munich.
I'm going to push back Audi tour from wed 3/8 to Thursday Morning 3/9......
Thurs 3/9 Take bus to Ingolstadt, to tour Audi, Then rent car and head North and find hotel either directly in Regensburg or bypass and stay in Nuremberg for night of 3/9.???I just do not want to affix anywhere in the dark....POSSIBLY train to Nuremberg and rent car there after visiting there???
Trying to figure out.
So now will only have Friday 3/10, sat 3/11, sun 3/12 for the "Loop"....and Rothenburg ob der Tauber is a Must!
3/13 Fly out of Munich 12:30PM
Thanks again for your input

"It still is an option 3/5 to rent car one way into Garmish and hit Linderhf, then Ettal, Oberammergau (probably not Landsberg?) on way to Munich."

Because so much is uncertain in your case about how/where you'll be spending time from 3/4-6, and because you fly out so soon, I suggested before and will suggest again now that you arrange to pick up the car on 3/4 in Fuessen. I see Autoeurope office in Fuessen is open only until noon on Saturdays, so pack up early, pick up early (9?) drive to the N'stein parking area, drive that pm to Garmisch for the night. On the morning of 3/6 you can figure out your route to Munich. All those places are worthwhile but who knows what you'll actually feel like doing that day? You could keep the car or arrange to drop it morning of 3/7 (I don't trust drop-off-box arrangements if office is closed by the time you reach Munich - I'd want an inspection that clears my responsibility for damages) - where? Whichever AE office is close to your hotel I guess. AE has multiple munich locations.

"Thurs 3/9 Take bus to Ingolstadt, to tour Audi,"
Sounds like you have those details from Munich to the Audi site worked out; I have no familiarity with this. If you don't either, using the rental car from Munich might make sense if you're using a rental later that day anyway.

About your loop... It's too many places, more of a wish-list IMO, but if you really want to try to hit almost all of them... Check your distances but Burghausen sounds like a big detour - I'd drop it. After Audi/Ingolstadt I'd consider visiting Regensburg - and then driving to Nuremberg for the night. On 3/10 visit Nuremberg, travel to Wuerzburg in pm (for 2 nights) w/a 2-hr. stopover in Iphofen. On 3/11 day trip to Bamberg and Coburg Castle in place of Burghausen - then back to Wuerzburg. On 3/12, W'burg in morning, Rothenburg in afternoon; drive to MUC airport for night, drop car (try Novotel at airport.) You will need to check the driving hours involved in all this.

Thurs 3/9 Take bus to Ingolstadt, to tour Audi

Which bus? Please note that there is a regular bus service only between Munich Airport and Ingolstadt. Go by train either to Ingolstadt Hbf. and take Bus no. 11, or go to Ingolstadt Nord and take bus Nr. X12 to Audi.