Get the Fly Idaho book...it'll tell you all you need to know about the various airstrips. While there are some options open to the Champ, most of the
wilderness airstrips are not going to be real viable unless you want to land at dawn and take off an hour later...a practice contrary to their intended use when they were grandfathered into the wilderness area, and one which will illicit strong opinions from both sides. Just a heads up on that.
Most Idaho
flying is actually pretty low altitude. You can cover most of the state at 8,500 msl. What gets people is the fairly high-altitude landing fields, and the VERY high DA, combined with operating in the bottom of deep canyons. The canyon flying is no joke...it's a completely different flying environment. The visual is foreign to most pilots, the approaches and departures are non-standard, and it's a unique microcosm of air currents. Canyon winds are amplified by orographic heating and the cooling effect of the rivers, and they will play absolute hell with anyone who doesn't understand them intimately. Even wide-open airstrips like Garden Valley can baffle pilots not used to flying close to canyon walls and descending towards trees and rocks and water. Many airstrips require descending below any reasonable go-around before the airstrip is even in sight.
Runway length is NOT a indication of whether a airstrip is acceptable to any given pilot if it's in the bottom of a canyon. That people regularly run out of runway at Johnson Creek (3,400 x 150 feet of perfectly manicured grass) is proof enough of that. Getting in and out of canyon strips requires discarding everything you know about standard patterns and approaches, as well as careful fuel management.
The magenta line on the GPS isn't even close to what your actual flight path will be, so don't believe the numbers it gives you. It's not uncommon for the actual flight path to be twice as far as the straight-line flight path, and that's in clear weather. Valley fog can be common in the summer, often closing McCall and Cascade in the mornings, which is severely inconvenient if you need to land there for fuel because you just came out of the backcountry with minimal fuel on board. On the other hand, you can't use many of the backcountry strips if you're carrying an extra ten gallons of fuel in a Champ...
The only way to deal with the DA and the canyon winds is to fly early. By noon winds in the canyons are SERIOUS for a low-powered airplane and unfamiliar pilot. Don't pay any attention to what the charter guys consider good flying hours...they've forgotten more about the wind currents than most people ever knew. Tied down and drunk by 10AM is the standard for private pilots in the backcountry, and 9:30 is better.
Even in summer it's not uncommon to have freezing conditions overnight, so you need to be able to pre-heat your engine in order to get out before the DA and winds make it too dangerous. My normal departure routine is to get up before dawn and start heating the engine so I can get out well before the canyon walls start warming up. To be fair that isn't always necessary, but in a Champ it probably is.
Also keep in mind that Idaho backcountry roads can be BAD. You probably
could get your 5th wheel to Johnson Creek or Warren or Big Creek, but you won't enjoy it...at all. I'd
highly recommend parking that thing before venturing onto any of Idaho's dirt roads. I always carried two full sized spare tires for my pick-up in Idaho, and was thankful I did on more than one occasion.
Stay
light, fly
early, and manage your fuel carefully, and a number of Idaho backcountry and sidecountry strips are within the capability of a
properly flown Champ. Just be extra-careful... No matter how many hours you might have doing "regular" flying, Idaho is a unique flying environment where most other hours don't count for much.
Have fun!