Seasonal site questions

We had our camper parked on a lease spot for 2 years. I can't help you much with the stabilization as we had pretty hard ground and I just used regular chocks under the wheels and the crank-down stabilizers in the corners. We would always empty the fridge and turn it off when we left. I'm not sure how these fridges are running full time with the heating element. Plus, we didn't want to use any electricity when we weren't there. Before we left, we'd always unplug the camper and lock the power switch to keep others off of our meter. Not that this was ever a problem, just being safe. If you have slide toppers, you should be fine with leaving them out. We always pulled ours in as I was always paranoid of leaks and falling limbs. Depending on how sunny it is, I'd get some tire covers to protect them from UV deterioration, but this should be done all the time anyhow. As you said, it's also a good idea to turn off the water when you leave, just in case a leak occurs.