Completed this trail on October 17th.
I can understand the reluctance in paying an entry fee just to hike this. But the Living Desert is a special place so I would recommend making a day of it and visit the various animals and exhibits in addition to the hike. The food in the Watutu Village is actually pretty good so have lunch there (along with a post hike cold beer). Then feed a giraffe or ride a camel or the old carousel.
We took the long loop and my Apple Watch measured it at 4.8 miles round trip. Sign in at the trailhead so they know if anyone got stranded out there. As already noted there is very little shade on this trail. So it goes without saying to pack plenty of water or Gatorade type drinks. The boulder field at the beginning had some standing water in a few spots and a large falling rock caught our attention pretty quickly. It climbs pretty steadily in spots and eventually tops out with a little covered picnic table. Great views from there and an easy descent from there. I would rate this as more moderate than "easy". But of of course these ratings are also based on weather and each person's overall physical condition. It was low 80's on the day of our hike.
BE AWARE-->This trail is dangerous for rattle snakes this time of year. In late March my sister-in-law came upon one while hiking with out son. Frightened her big time. And now it is reported an actually bite on a 17 year old hiking on Sunday. My advise is to 'take a break from hiking this time of the year's. Odds are that you won't get bit but why take the chance?
This is a great hike. I would never pay to hike. I have hiked it many times while visiting the Living Desert as my primary objective. The beautiful part of this trail is that you can do the whole thing or chop down the total length a couple time before committing to the entire distance. this option is great for kids, the elderly or if it's just too hot.