Sand Hollow is an amazing place with some great trails. A great mix of Dunes, Rock Crawling, and some higher speed stuff. If you plan to stay within 5-10 miles of Sand Hollow, there’s probably 3-4 days worth of riding if you don’t want to ride the same trails every day. At Sand Hollow, you’re also within machine driving distance of the AZ strip and the trail system up that way so if you’re not afraid of a longer round trip, there is access to some great trails in southern Utah.
As for timing, its hot in that area from May through September. I’m talking regular 100 degree days. It does cool off at night to mid 70’s though.
I’m from the area and my buddies ride there regularly and can give you some pointers if you end up heading out this way.