Here is some honest advertising by Relion LFP
"More Usable Capacity 25-50% more capacity than lead-acid equivalent"
The OP wants to camp off grid in a TC for a few days where he runs a few things but not the furnace or bigger inverter loads, so he seems to think one 100AH battery will be enough as long as he has enough solar to keep up. With furnace and the usual things, it takes one battery per day.
He could do his loads with two FLAs and "enough" solar. He is hoping the one LFP will do it, being like 1 and 1/2 batts, which it might with no furnace time.
The money side of things is obvious and up to the OP for what is "worth it" .
EDIT--"enough solar" is the same for either battery bank size. IMO he will need 200w or more and 100w is not enough. On my budget, YMMV, I would get more solar with the money I saved from getting FLA instead of LFP. But I am not the OP!