Our family will be staying on Lake Constance at Meersburg and from there, driving to Oberammergau. Does anyone have knowledge of the route options? One goes to the north, and another goes through Austria and I'm wondering if that route would more a more difficult drive.
We drove most of this route twice last week. We were coming from direction Ulm, Germany to a ski area by Landeck, Austria. You indeed have a few options. One is relatively flat, boring, high speed autobahn 3/4 of the way, which is Meersburg east to the A96 past Memmingen. Then south on the 17/23 highways which are secondary roads, one lane each way, but scenic. This is the google maps way. Your other option is a bit longer but very scenic the whole way...when you're not in a tunnel. Go east from Meersburg, head south past Bregenz, which is then autobahn. Take the E60 east to Imst and head through the Fern Pass. This is straight through the heart of the Alps and very beautiful. Driving is tougher as it is a mix of autobahn and secondary roads with a lot of tunnels. Plus there's a 8.50E cash toll. From the Fern Pass head east on 23 through Garmisch-Part. which is an easy 2 lane road. Lastly, you can go Meersburg east to the 12 to A7, south through Fuessen, then 179 through Garmisch or the backroad past Linderhof. This way is personally, a horrible drive. Winding road, locals coming on and off the road slowly, this is my last choice. If you need to make good time and get from one destination to the other, take the A96. If you're in Europe to see the Alps and get to know the countryside, definitely take the E60 it's stunningly beautiful. There's plenty of gas and rest stops each way you decide.
The drive on the north side of the Alps is mostly on secondary roads over open, rolling terrain. It's no more difficult than any other similar road in Germany, other than to note that the driver's gaze will probably be drawn consistently off the road and to the mountains. I haven't driven most of the Austrian route you mentioned.
The Deutsche Alpenstrasse route that crosses into Austria is an easy, well-marked drive but it's no Autobahn - it IS hilly and has plenty of curvy sections. Assuming decent weather conditions, I would drive it again in a heartbeat... the scenery is beautiful ! If you decide to take this route there are two things to note: a). your transit time will take a bit longer than you would think just looking @ a map, since you are going up, down, and around hills and mountains; and b). make sure you have a full tank of gasoline before you leave the Lake Constance area. There are not too many towns along the Deutsche Alpenstrasse, so consequently few gas stations along the way.
Have done the Meersburg - Oberammergau route several times & here's the route I like (no tunnels!): Take the B31 to Lindau & get on the A96 north toward Memmingen. Go about a mile and get off at exit 4 onto the B12 going toward Isny / Kempten. The B12 eventually becomes the A90 (Kempten bypass) which runs into the A7. Take the A7 to Fussen, and just beyond Fussen take the B17 to Schwangau...you're now at Neuschwanstein Castle! Continue north on the B17 to Steingaden and take the ST2059 east... just a short way down the road is the entrance to the Wies Kirche! Continue to where the ST2059 runs into the B23. Turn right on the B23 and you're on the way to Oberammergau. Total driving time is about 2 hrs 40 min. It can be a little slow on the B12 if you get behind a truck, but the rest of the route is rather easy.
Of the approx 16 weeks I've spent in Germany, four have been in the Oberallgäu, in a little village between Immenstadt/Sonthofen and Oberstdorf - in the middle of the area about which you're talking. I've been by rail between Friedrichshafen and Sonthofen; the rail line parallels the beginning of the Alpenstrasse to Sonthofen and is relatively flat, a little hilly around Oberstaufen. And I've been by bus from Sonthofen to Füssen by way of Hindelang, Oberjoch, and Nesselwang; that's all part of the Alpenstrasse. I haven't been on the part from Füssen to Wieskirche, but I have been between Wieskirche and Oberammergau. Most of the Strasse from Lindau to Oberammergau is pretty flat, rural, scenic. The part from Hindelang to Unterjoch is perhaps the most "Alpine". The road out of Hindelang goes by switchbacks straight up the side of a mountain, and that part is pretty exciting. I was glad I was in the bus and able to enjoy the scenery without having to keep my eyes on the road. But it is definitely worth going by that route rather then through Kempten.