Towing with a 3.73 F250 6.2L, will a 4.30 axle help ??

For 2-3 times per year, I like the wheel swap idea. Get a nice set of 17" takeoffs from someone (probably $500–1000) and put swap them when you tow. Much cheaper than a regear and should yield similar results. If you don't like it sell the takeoffs and get a diff truck at that point. Good luck with your decision.