DH's dad did most of his repair work and taught DH and his two brothers. Brothers don't do much of their own though. DH did mechanical work on and off on during his lifetime. DH also worked and flew on helicopters in Nam.
Son was interested in it from word go. Grandpa use to bring old lawnmowers for him to tear apart. It didn't take long before he could take them apart and put them back together either. He actually made money during his school years during the summer repairing them. Of course that graduated to cars and other vehicles.
He now does engineering work for a major company around. Watching him do it on a computer is pretty impressive.
He still does most of his own (and some of ours and friends) repairs.
That is an awesome idea maybe this coming summer have some spare rc truck parts around all it should need is a receiver speed controller and 2 high torque electric wheel chair motors and that should do it can skip the servos for stearing would go with tank tracks instead cause I also have a fairly steep hill I think it would have issues climbing. Shouldn't give me ideas like this I don't need better ways to chase the neighbors cats the helicopters cars and trucks do that well enough already.
I would watch your center on gravity if the hill is that steep. I would suggest a springloaded stabilizer. Probably 1.5'-2' long.
But that really depends on the size of the mower.