I wound up doing a really fun solo ride in the Don on my cross bike. I was totally surprised at how well it rolled through there. The only sketchy stuff were a couple really steep descents (I missed my disc brakes) and some roots covered in leaves. I can't help but want to try out a 29'er now... it just felt like I had so much more momentum today on the big wheels. Add a touch more cushion/traction and it would be killer.