Don't call up beforehand and let them know you're coming---that gives them a chance to clean up and act right.
Stop by at 6am when the residents are just being woken up. STop by around 3 when things are just settling down after lunch.
Talk to the residents and the staff. Find out what kind of food is served, and what that particular nursing home does as far as extra-cirrucular activities for the residents.
Garden Village is one of the nicer nursing homes in Yakima. Go here first, and compare what you see elsewehre to Garden Village. You'll be amazed at the difference that's out there.