FR Super Cub taxi problems

Well, I bought the FR Super Cub Extreme package a while back and have been flying it a bit. I was wanting a good bush plane with a little more speed than the A2A Cub, and a little more oomph for higher altitude strips.

So far, I like how the plane flies, but I've been flying it at regular airports for the most part. The past couple of days, though, I've flown it to bush strips along the Salmon river country. These are the kind of strips the Super Cub was made for, I would think. She lands fine at these strips, but when I try to taxi her to turn her around or back taxi to the end of the strip, all hell breaks loose. It's as if her tundra tires have sunk into the ground. I have to apply almost full throttle. The tailwheel lifts but she doesn't go anywhere. And no, I don't have my brakes on. When I do get her moving, it's impossible to keep her on her gear. I hold full back stick, and move at slow speed, but she'll plant her nose or start doing worse gymnastics. It's very frustrating.

These are backcountry strips, with rough terrain, but then that's what this bird was designed for, and I fly a lot of other aircraft just fine at these strips, the A2A Cub, and the Birddog, and the Scout, and the C185. Shoot, I've flown the RV-7 at these fine. I don't have any problem with any of those.

Is this a general experience with this aircraft? Does anyone know how to alter the aircraft.cfg to tame her ground behavior? As it is, these planes are unusable at the precise airstrips I bought them for and that they are designed in RL to fly at. Any help appreciated.