Our Springdale (2011) did have a winterization valve on the rear of the water heater and two (hot/cold) low point drains as well as a fresh water tank drain. Otherwise, there were no winterization valves. Actually, none are necessary. Just turn the valve to bypass the water heater, remove the anode/plastic plug (depending on Suburban or Atwood) open the low point drains, blow out the plumbing lines (optional) install RV antifreeze (don't use automotive antifreeze) drain the FWT and you're essentially set for winter. There's an expanded "sticky" that describes the process in detail located at:
http://www.keystoneforums.com/forums...ad.php?t=20540