Assuming you have a generator, it may be worthwhile instead to look at small 120V air compressors; some of them are about the same size (but not shape) as the portable air tanks. Even without a generator, electric outlets are often easier to come by than compressed air.
I have a Fini AirBoss in my motorhome and it serves the purpose admirably. Lowes (among other places) sells them, at least sporadically, for around $100 give or take, depending on the current sales and whatnot.
A 5 gallon tank filled to, say, 125 psi is not going to put an enormous amount of air into a LT truck tire at 80 psi; it would for sure be less effective than when used for car tires at maybe 30-35 psi.