Saturday we went with my sister and brother-in-law to climb the mountain with the R on it near Rexburg. We brought the baby because we heard it wasn't too hard of a hike but it was really pretty steep. Once you get to the top you the walk is pretty even and the veiw is amazing. The hike up is about 15 minutes but around the top you can spend lots of time if you wanted to walk around the top.
Directions to the trail head: if you head out of Rexburg on main street and about 8 miles out of town turn left on N 3700 E, the first road that crosses it should be Twin Butte Road, turn right. The parking for the trail will be on your left.