Wow amazingly weird advise so far!
Your plan makes perfect sense to me. My reasons:
Real Estate is at a historical peak right now and has no where to go but down (declining demographics, increasing interest rates, increasing tax rates).
You are not quitting your job (just don't tell them your plans - people react much like the folks have on here so far).
Double check your assumptions about zoning.
Don't buy a new rig. Go with used. A nice older Teton Home or DRV Suite.
Consider building a large garage with upstairs apartment on your lot.