I do have a 1500 inverter but only plan to use it for the TV & DVD player (roughly 200 w together).
I also have 2 much smaller batteries that came with the trailer, they are refurbished interstate 12v's (Interstate Econo power). I have no idea what group they are, all info decals have been removed.
My group 29's are both Interstate RV/Marine batteries that I got a few years back for our Pop up trailer. We did 3-4 four day camping trips every Summer, the batteries held up great, I think the lowest they got was 75%.
Every Fall I remove the batteries from the trailer and keep them on a float charger on my work bench in the garage with caps loosened.
Again, I do have a 1500 watt inverter but I do not plan to use anymore than about 500 watt max.