Considering all factors, one which was box size, I installed my LiFePO4 under my bed in the pass through storage. Easy-peasy, disconnected the old battery on the tongue, freed up the wires. Drilled a hole through the floor and connected the new battery inside. I added a battery disconnect initially. Only needed one more cable from the disconnect to the battery, otherwise, used the stock cabling.
Since then I’ve added a couple buss bars, second battery, solar connections, shunt battery monitor, and a 2000 watt inverter. And lots of thick wiring.
Leaving a LiFePO4 battery on a trailer tongue unsecured is money in the wallet of a thief.
FLA batteries get stolen from storage lots all the time and are worth at best less than half the $$ of LiFePO4. And sleeping nearby, if plugged in at a CG, you wouldn’t notice a brazen thief taking your battery if your converter is working.
You just need a retaining block and/or strap for interior battery mounting of LiFePO4. No venting, no liquids, no acid overflow concerns. And it can be mounted in any orientation, whatever is convenient for ease of wiring.