group 24 & 27 batteries ?

What are your plans for dry camping? Trying to go for extended periods with no generator or minimize how often you have to run a generator? We have been dry camping (typically 2 weeeks at a time)for years with a single quality 12V SCS200 115 AH (Gr 27)Trojan battery but we run our EU1000 generator every morning to keep the battery nearly fully charged. Our power needs are modest since we do not need an inverter but only need power for vent fans (or furnace in the morning depending on the season), water pump, trailer electronic controls and LED lighting.

I agree you should have no issues with paralleling two batteries (if you really need the additional capacity)as long as both are in good condition.