Not much of a coffee drinker, but it appears that French press is more popular than 12V gizmos, in this scenario.
250-300 AH bank - total bank, not "usable 50%" - might work for your needs. Especially if there is none or very little use of microwave and no other high-power 120V items.
2 pairs of 6V batts for a total 500 AH would've been better, if you can carry that much, but with 250 AH and a big solar to charge it quickly it might just work for you. The beauty of a big solar is that you always have a few amps trickling in, even when it rains.
