For the batteries, if you are not going to be doing any heavy inverter setup, just go to Costco/Sam's Club and get some 6v deep cycles. The cost for maintenance free is not worth it in my opinion. Get those cheap 6v batteries or go up to lithiums.

For the hitch, did I miss something? Thought we were talking about fifth wheels? EDIT: my bad, missed the 297rsts part

I would get a propride and be set for any trailer that comes your way - I hear nothing but good about them (besides the price of course!).