you are doing right. a few more things i can think of -
1) make sure cover all tires. don't leave any portions of them uncovered
2) no need to crack windows on the cover
3) i use star tron in every winter, works great https://www.amazon.com/Star-Tron-Enz...BNGV9MS3Q1KNK4
. other brands work too.
4) disconnect batteries. if you don't have a solar sys, you may take the batts with you and charge them up periodically. it will extend their lives drastically.
5) shut the propane main valve off
6) leave fridge doors ajar
7) if you have battery powered devices, such as co/smoke alarm, clocks, etc., take the batteries out.
from now on to march next year the weather in vegas is generally mild, but there will be a few days in jan cold at nights, so, you mentioned it already, dump the water. don't think winterizing is necessary though.
wait others for more to add... good luck.