The sport cub is a nice airplane, and I've seen them being built. I own its predecessor, a 90hp. PA11 with flaps, similar in weight and performance. I've also owned super cubs, but never a 180hp. one.
As others have said and will tell you, keep it light, and it will do fine. Do not expect to load it with a passenger and camping gear for 2 and jump off the ground on a hot day at 5000' like a super cub. There is no substitute for horsepower, and you cannot fool gravity. With a bit of discretion, I believe it would do fine on those Idaho strips.
The benefits of the 100hp. mill are many, not the least of which is the 5 gal/hr fuel burn while traveling at virtually the same speed as it's 180hp. big brother. The fun factor is extremely high.
Unless you just have to have a new Cub Crafters airplane, there are quite a few very late model Aviat Husky's on the market right now, for slightly more than half the price of a new Top Cub. A very capable bird that might be worth considering. Or, let me be the first to say that you could just buy a Maule.
Good luck, let us know what you decide.
gb