thats a 26" bike? I'd probably use a 26 x 1.7-1.9" semi-slick tire on that for mostly suburban occasional trail riding.. I've got a 26" 'cruiser' that I put Geax Evolution on, its a nice rolling tire, handles hard pack dirt just fine.

That Dyad rim I mentioned is, AFAIK, only a 700c/29er wheel, so you'd need some other rim for 26" but there's tons of sturdy 26" mountain bike rims available, many in 36H. a properly spoked 3 cross 26" wheel with stainless 14ga spoke will be strong as heck.