If it's a question of only using the hotpot while driving, an alternator upgrade would solve his problem. The small frame Delco CS-130 alternator is not a good alternator design to start with. If he later goes to a bigger battery bank the alternator and a bit of wiring is already there.
And another side note. Genuine Delco is better than a copy and 99.99% of remanufactured alternators are junk. A Delco re-man would be the best of the lot.
The gull Wing sawed-thin-fin rectifier is not cheap so rebuilders slap anything in that seems to work. They do not bother to test and grade used rectifiers. And only the Delco 1116435 and Transpo D411 voltage regulators used to hold up under heavy use. Fussy fussy Mex.
If something has an awesome record for durability and reliability I could care less about a warranty. Most big name AGM batteries do not fail early on. They tolerate no manufacturing errors.
With a tiny rig and big battery appetite I would consider an XT 2-story Lifeline and then have a shop build a stout cage to be bolted alongside a frame rail. Perhaps six 1/2" stainless steel bolts with nylon lock nuts. Big rig mud flap for a box liner.