I understand your reluctance to use the fridge. RV fridges, especially older ones, can be finicky and, as said, there is a learning curve. In addition, given its age, this one could well be on its last legs.
It wouldn't hurt to test it on electric, though, if for no other reason than to verify whether the cooling loop is working. If it is, you could (1) use it on electric only for a while to see if the electric-only plan is going to work for you, or (2) sell it for a little $ online, knowing that it does work.
If you do decide to remove it, just cap off the LP line and leave it and the wiring in place should you (or a future owner) decide to put a 2- or 3-way fridge back in. For safety you'll want to do a drop test of the entire LP system before reconnecting the tank.