First of all, welcome to the full timing lifestyle! One of the first lessons you learned (banks get nervous) when you tell them you are full time and really don't have a physical address. I guess they figure if you only make that first payment and then no more money comes their way it would be sort of hard to track you down.
As far as insurance goes I think you will find there are a few companies that will insure your RV for full timing. We use Progressive, but there are a few others also. Get ready to spend some additional money.
Our summer base CG in central Illinois sets up a few spots for winter use. They do not allow skirting. They have frost free water hydrant at each site and they place a barrel over it with a heat lamp inside. You are responsible for hooking a heated water hose from the hydrant at your site to your trailer. Most winter campers there use PVC for their sewer, which they insulate well.
As far as propane. There are numerous companies in that area that will deliver as many 100 pound rental tanks as you want. The only requirement is that you have to allow them to make the hook up. Then they will come by throughout the winter and fill them as needed.
I would suggest you expand your search a little wider to find the correct CG that has experience with winter campers. There are RVers that do it during the winter in Alaska so I am sure you can locate some CG managers smart enough to figure it out in MO.