You are at "elevation" here, it's arid and dry...it's what is called an "alpine desert environment"...you'll dehydrate quickly and burn even faster. But just some basic precautions and common sense allow you to go anywhere in Idaho and pretty much do anything and have a real ball doing so.
If you leave town and main roads for the deserts, bluffs or canyons be sure to let someone know your destination, route and the latest you expect to be back.
Idahoans are a friendly but rather pragmatic and independent pioneer thinking lot. The Twin Falls area up to Mtn Home is the home of old Basque shepherds and free range cattle ranchers. They aren't gonna put up signs or barracades to keep you "safe". They figure that if you aren't old enough or mature enough to use common sense then you should still have your momma with you or you shouldn't be out on your own in the first place. So if you fall down a cliff, drown in a backwash or wadi, get bit by a snake or skunk, #####ed by cactus or porcupines or just get run down and gored by a mule deer or free range cattle...well, it's considered YOUR fault.
Wear light loose cotton clothes, long sleeves, a wide brimmed hat, sun screen and good sturdy shoes if you go into any of the lava rock areas. If you pass through a cattle gate leave it EXACTLY in the same position you found it - Open OR Closed. Be careful not to turn an ankle in a cattle guard at ungated fences!
If you even get NEAR sagebrush you WILL get ticks so check for them (armpits, hairlines, waist band area, behind the knee and in the groin area) just before you shower. It usually takes a deer tick 2-6 hours to get deep into your skin so they aren't hard to remove...but you have to look for them.