cut a hole in the car cover where it would cover the dash, stitch up the edges to prevent unraveling, Bob's your uncle 👍Mark,
I'm sure once the paint cures it could probably be color sanded and buffed. However, I think it looks great as it it. Like you said, it's a working wagon. My car had been a daily driver and working wagon for many years until I took it off the road. It's seen a few NY winters before finding it's way down here in Flora-duh.
I recall back in the late 60's, early 70's, I used to help my dad do house painting, mostly interior work. I painted a customers kitchen cabinets with Interlux paint. They came out very nice and lasted for many years. I impressed myself. 😛
I like your battery tender idea. I guess the car cover renders the solar panel useless?
alternatively, run the cable out the door jamb, close the door, punch small in cover to feed cable thru, place solar panel on top of cover