STEVE
it sounds like you have done enough reading on this forum to know you can't go a week on only one battery unless you use the trailer as tent , turn off the fridge and lights
It sounds like you want somebody to tell you , that you don't need a generator
Get a ice filled cooler and use the tt as a log cabin and maybe you can do it
Other wise borrow, rent, or buy a generator
For what you want, you could get by with one of those little harbor freight 900w $99 2 cycle generators, a pretty inexpensive investment
It's not high power, so don't run the battery dead
Run it every other day for 2~3 hours
A total of 3 or 4 times for that week