Just got back in from the weekly California run. In San Diego I found some Michelin XDE M&S 's for $277 per tire.
Not too worried about a harsh unladen ride, truck turned 340,000 today and I'd bet at least 325,000 have all been towing.
225 or 245 size? That's about what I paid for my 245's 4 years ago. They are a great tire. A little noisey, but fantastic traction and wear.