Senior communities I would recommend you check out are Englefield Greens (on the Bench), and The Orchards at Fairview/ The Orchards at Cloverdale. There is also a development in Meridian, but it is a life estate system rather than a straight purchase. If you have questions about any of these communities, please feel free to get in touch.
I can research other senior developments, but one in 83709 that comes to mind is Spring Creek off of Overland. There are currently 25 homes available in Charter Pointe (this number does not include any contingent short sales). They range from 1000SF to 3600SF. What size of home are you looking for?