Stay off the hill to north of the trail ride into the riding. It doesn't look that dangerous, but it is. They have slide paths named sisters 1 through 7.
Then use your eyeballs everywhere else.
Splains Gulch has safe kindda fun flattish type tree riding, and is a good spot for beginners to learn to tree ride. Find a map, there's a loop that gets you to Splains. East part of the loop has some high consequence avi paths above trail with another 1000 below the trail to get carried before you're burried. West side part of the loop is pretty safe, and how i go in and out when avi danger is high.
Some safe play up towards Irwin lake also, but also some of smaller hills need to be given respect as there's traps below many of them.
Just watch your terrain angles, and look for traps.
CB has it's own avi report, and the guys are pretty good. Check it, and pay attention.