Yesterday, as I contemplated how to recover my flying miner, I considered three options:
The first was to disassemble it, then reassemble it in a safe location, correcting some of its design flaws. I dismissed this as boring.
The second was to Kerbal it out of that location. I decided I wouldn't learn anything that way, so that became plan "B."
Plan A was to adapt my Rover into a miner, and rescue it that way. So I attached a couple drills on the front, drove to the shallow trench my flying my flying miner dug before it decided to pitch down into the ground, and started digging. This is the result:
Gravity is a harsh mistress.

In case you can't tell, it's on its back, after pitching down just like my flyer did.

Woke up this morning realizing exactly what the major flaw in both designs are: the front inventories filled up first, which caused both vehicles to pitch down. With all the weight in front of the Rover's front wheels, of
course it would pitch down. And once it reached vertical, with the rover being slightly top heavy, it would tip over the rest of the way once I started moving its inventory manually.
I did try to Kerbal the flyer out of there after this disaster, but to no avail. I'll be dismantling both vehicles (the rover needed to be redesigned anyways) and rebuilding both from scratch. There's a sorter block I haven't played with yet, so that should ensure that the weight distribution will be more even.
If I can get both vehicles working the way I want them to, I'm thinking of upping the challenge by restarting on the alien planet in the solar system. And perhaps adding enemies in as well. Time to add more survival challenges to this survival game!