Hey Mark, While camping in Buffalo(Indian Campground...(nice people,nice park) we did a long day trip loop that the last section was 16 from Worland east back into Buffalo (toad trip). The road between Worland and Ten Sleep was very good and an easy drive. After Ten Sleep, it gets pretty steep. The road was excellent but will require some slow going on the steeper grades(long and some I would guess at maybe 7 to 9 %. We did see a few class A's towing but most disconnected...the 5'ers were muscling up the grades with not much effort. Your 3500 should do just fine from what we saw.
BTW, in Ten Sleep, they put on a pretty good rodeo everyday and worth the stop.
Also, just outside of Ten Sleep (6-10 miles past and heading east) there is a campground on the right at the base of the up grades of Bolder Pk. Sorry, I should have kept better records, but the campground(on the right) is on a road that parallels 16 on the opposite side of the canyon that turns into dirt and reconnects with 16 near the top of the pass. That road is worth spending a night there at the CG and driving with the truck. !6, IMO is much tamer than 14A further to the north. Enjoy the trip, it's a good one. Bob
One other note, Mark. As I said, it was a long day trip and we were caught after dark on the last third of 16 into Buffalo. I never saw so many deer on a patch of road as we did that night...FYI.