The bush trips are fun but I don’t think they are only for sight seeing and from memory, Asobo didn’t tell us we had to be careful with fuel so if you just jump in it can bite you. I’ve only done a couple because I hate Asobo’s flight plans in them. So you also need pay attention to leaning the engines and flying accurately, no detours or getting lost.
Whether some may not be completable or too hard, I don’t know.