I commend you on your efforts, desires, and planning.
I've been very lucky in life so I can not speak directly to your issues. But I have learned a few things that might help. The first is yes, you can have a good retirement RV'ing on SS. I've seen it done while on the road.
Second, what goes up comes down, and what goes down comes up. Ten years is an awful long time for an investment. You just may find yourself making money on that real estate. This isn't the first time in history where home owners became upside down only to later find themselves in a hot market.
Keep the faith, and much luck to you.
On Edit:
Let me just add one more thing. Many of these blogs and pictures paint a very rosy picture of the lifestyle. The simple truth is it has it's issues also. Nice thing about pictures is they are not 360 degrees, and blogs are from just one perspective. Case in point is a FT/work camper that I have much respect for. When I visited his site that his blog/pictures made look wonderful it was really a site full of busted up concrete next to a motel of homeless people sitting on old chairs and couches outside trying to beat the heat. Whatever you do don't jump from the frying pan into the fire based on an unknown lifestyle that is portrayed on the internet without doing due diligence.
