[folivier]

Years ago on #486 I had 4 of the 6 8D lead acid house batteries go bad while on a summer long trip through Canada. Disconnected the 4 bad ones and was able to do ok with the remaining 2. Even did a few nights boondocking although I had to run the generator once or twice to top off the batteries. This was with NO solar. The biggest draw was the Amana fridge and aquahot for heat and hot water.
So you should be ok with 2, just have to run generator occasionally if dry camping. If driving from power pole to next your alternator should keep up with your fridge usage.
Should have mentioned that I was in a similar situation with planning a LiFePO4 upgrade (which I did that winter) and didn't want to spend the money on replacing the LA's then have to dump them.