Quick question about buying rail pass while in Germany

You should be able to get reservations at the DB site now if they're available - without purchasing a ticket.

When you go to the http://bahn.de/en website to look for a connection, click "Seat only (no ticket)" instead of the "Search" button next to it. What follows is exactly the same as for buying the ticket but you only buy the seat reservation then.

A 4-day twin 2nd class flex pass is 308 EUR, so the average coat 77 EUR/ travel day. I see Sparpreis tickets for your first travel day(Sept 3 or 4) as 38 to 48 EUR for two. How are determining the point-to-point prices?
Even going out to the max of a 10-day pass, you are paying average of 52.30 EUR per day.

For those of you suggesting that I buy the reservation only for now - do you think I need to purchase the reservation now rather than doing it all at once when we get there? Do they ever actually run out of seats?

I've been traveling in Germany over the last 4 decades and I have never bought seat reservations - only when they came with the ticket automatically. I'd only do so if I had a large group that needed to sit together or perhaps if I were traveling over a holiday period, when overcrowding is typical. IMO seat reservations would be an inconvenience if I had a rail pass, the point of which is usually to have scheduling flexibility - and the reservation locks you in, not just to a specific train but to a specific seat or seats in a specific car that must be hunted down when you board.

So then I think I'll buy everything when we get to Munich? One wrinkle - we are venturing across the border to Alsace for a few days and one of our more expensive trips will be from Strasbourg to Mainz. I think the Flexi-pass covers this but I'm not sure. Any insights?

Also we will be using the Konus Card in the Black Forest for several days, and then are going to take a train from Gengenbach to Strasbourg. I'm going to assume that the Konus Card covers us to the border and then was planning to pay for the rest of the trip somehow at the station. Since it's a short trip I'm assuming it's inexpensive and am not considering this a train pass day but rather a point-to-point day.

Thanks!

Kehl to Srasbourg is only 4 EUR per person, so going in on a Konus card you need an advance ticket if you don't want to have to get off the train to buy a ticket. You might even be able to buy on the train, as is often the case with small German private railways like the OSB (Ortenau S-Bahn). At the least, you should be able to buy them from OSB ticket kiosks.
Strasbourg to Mainz, if you go by way of Kehl, just buy the 4 EUR tickets to Kehl, then the rest of the journey is covered by the German Rail Pass.

I'm going to assume that the Konus Card covers us to the border and then was planning to pay for the rest of the trip somehow at the station.

The Konus Card covers your trip till Kehl on the east bank of the Rhine. From there trains and, more frequently (every 8 to 10 minutes), busses go to Strasbourg:

http://www.schwarzwald-tourismus.info/Media/Attraktionen/Linienbusverbindung-nach-Strassburg

I've taken the Offenburg to Strasbourg train a couple of times. You can buy the Kehl to Strasbourg ticket at any DB ticket office. It's probably easier now to just buy at bahn.com.

I've bought rail passes at the Frankfurt airport, usually with little waiting. The only disadvantage is the web site sometimes offers deals that the local office doesn't offer.

In over 15 years, I've only had to stand on one reservable train. That was an ICE from FRA to Karlsruhe on Dec 26, a German holiday. Although every seat was occupied, most, according to the reserved lights, had not been reserved. Half an hour later, when we got to Mannheim, lots of people got off and we were able to find seats before more people boarded the train.

A few years later, I was buying tickets at FRA for the same train (although not on a holiday). I asked the clerk if I should reserve a seat. He just said, coyly, "You can if you want to". I didn't, and I was one of three of four people in the entire coach.

Unless I knew it to be a very busy time, or it was a long trip, and I didn't want to stand the whole way, I wouldn't bother with a reservation.

The web site bahn.com will show the seats that have been reserved (or are available) on a particular train. Be sure to check the 'Reserve a seat only' box. You have to scroll the cabin graphic to see the next car(s).

Strasbourg to Mainz, if you go by way of Kehl, just buy the 4 EUR
tickets to Kehl, then the rest of the journey is covered by the German
Rail Pass.

For 2 month out, I see SavingFare tickets for only 48€ for 2 people (plus 4€ ea for Strasbourg to Mainz). Why waste a rail pass day?

Strasbourg to Mainz, if you go by way of Kehl, just buy the 4 EUR
tickets to Kehl, then the rest of the journey is covered by the German
Rail Pass.

For 2 month out, I see SavingFare tickets for only 48€ for 2 people (plus 4€ ea for Strasbourg to Mainz). Why waste a rail pass day?

Thanks for all the info! I presume we don't actually have to get off the train and get back on at Kehl? It's just a payment thing, right?

If you want to go all the way by train you change trains at Offenberg (usually not a fast connection) and then, yes, as long as you have correct tickets you would stay on at Kehl.

You could also get off at Kehland get the bus or tram right to the part of Strasbourg you wanted to reach - the station in Strasbourg is not right in the centre of town.