Don't know where you live, exactly, but I live in "far" southwest VA and we pulled our 3500 lb 17' long hybrid with a 2001 Chev 1500 with the 5.3L for several years. It wasn't the fastest thing on the road, but it pulled it OK. We would NOT be doing 65 mph when we reached the top of the mountain, but we weren't going 40 mph, either. We would slow down to 50ish on the long, steep grades (like Christiansburg, mile 122).
I have no recommendation on the brake controller because I really don't remember what we had on the truck.