Would agree with you, anything is possible but guess large areas of Powerline Rd can be ruled out as CAP etc would have no doubt found a plane located in open and fairly barren land. As a total work of fiction and imagination, I could conceive a low flying plane making slight contact with powerlines, erratic flying shortly after while pilot regains control and accesses the situation. Climb to an altitude that allows for either radio contact, or safe to return to base, but doesn't make it due to the damage known or unknown that has occurred. Total speculation on my part though.
Regards
Hitting a powerline with a Citabria tail rudder could also account for irratic flying behavior, Like the tail waving up and down. (refer Rawley report). But like you say, it may have felt stabile enough that SF thought he could make it back to the ranch. A 15-20 minute flight back up towards the FM ranch could have put him into some rought terrain. It's all just more speculation but does present some interesting possibilities. That cross-over point is 17.5 miles from the Flying-M ranch. And it does cross over some pretty rought terrain.