Hole in the Rock is one of the many free attractions in the Phoenix/Scottsdale/Tempe area. It's not hard to get to but that may be a good (almost anyone can get up there whether they're young or old) or bad thing (since it's accessible everyone will be there). I would suggest going on a weekday and at a random time rather than early in the morning.
The parking lot for Hole in the Rock is 'attached' to the Phoenix Zoo. The lot is significantly smaller but much closer. We parked next to the Zoo and wandered halfway and decided to move the car closer. When we arrived at the 'mountain' there was a path that wrapped around the back of the mountain. It has a slight incline and some 'steps' so nothing too hard.
The "hole" is the entrance to get from the back of the mountain to the front. This makes it really hard to take photos because folks are always entering and exiting. But if you're in a big group I'd suggest asking someone to be a lookout. If you're only two folks, like us, makes friends with other smaller groups and watch out for each other.
I decided to give it an "A-Okay" rating because it's a go once, tourist type place and I wasn't a fan of the view or the business of it. It's not something I'd tell friends to check out if they were in the area.