Velocity's website specifically suggests using the 26" Aeroheat rim for loaded touring and tandem use, but if I were building a wheel to put on the back of a tandem/touring bike I think I'd use something more than a 480g Aeroheat. Especially when riding across the country where reliability is paramount. I wouldn't expect it to give you an issue on the front though.

Re FB's comment about tire pressure - now I'm curious what pressure you're running because with a 2" wide tire you shouldn't need that much. At least I wouldn't expect you'd need enough to break a rim.