I recently built my own LiFeP04 230AH battery. I also added solar, inverter, automatic transfer switch etc. The total system cost me over $3K.
If I had it to do over again, I would buy one of these total 110V systems that you can simply plug your camper into and use it. It would give you 110V for your outlets and could be wired into your converter to charge a small 12V AGM battery for your lights & W/P. I would also install about 400W of solar panels.
This way, you could also run some of your home appliances, (like your refrigerator 24/7) from your portable generator. Then when you sell your TM, you don't have to include your expensive LiFeP04 set-up.
https://www.amazon.com/BLUETTI-Porta...1-1e5b3de13370