Need some suggestions on upgrading batteries for dry camping

You have several choices. AGM batteries don't have to be vented. You can buy a sealed battery box and vent to the outside for Lead acid batteries. A lot of TC have the battery box inside and many boats have the battery vented this way.

I have 2 group 29 Lead acid batteries that will only last about 2 days running the fridge and a few lights. I added 165 watts of solar and this seams to keep them up without running the generator. I've only tested them on one trip so far and it was mixed camping.