Park Here: 38.445934, -111.190708 and work your way to the coordinates: 38.4418188,-111.1952917 and this will be your photo spot.
I recommend a 4×4 or higher clearance vehicle for this road, especially if coming from Hanksville. The road is rough and high clearance is necessary in some spots. There is NO service out here so someplace you do not want to be stuck.
Camping is not permitted at the Temple of the Sun and Moon or anywhere else along the Cathedral Valley Loop except for one spot, the Cathedral Valley Campground which is quite a bit further on from the Temple of the Sun and Moon.