My family just took the tour of the Lewis and Clark Caverns near Three Forks MT and had an awesome time. The paved trail up to the entrance to the cave is approx. 3/4 miles long with an elevation gain of 300 feet. The hike up is pretty strenuous if you are not in shape. It was awful hard on my knees. There are benches periodically on which to rest if needed, however, few are in the shade when the afternoon sun kicks around to the trail side of the mountain. The trail back down the mountain from the exit of the cave is a much easier walk, however, it is not paved, but is dirt and gravel. There are no rest rooms along the trail or in the cave, so you need to take care of business before you start up the trail. You will also want to take a bottle of water along for your hike up as there are no drinking fountains once you leave the visitor center. There are garbage cans at the top for empty water bottles. For those who are able to make the trek up to the mouth of the cave, the tour is well worth the effort. The tour of the cave itself is awesome. It is amazing how many different looking features their are. You will have to descend down a lot of stairs as well as ascend them, and there is one place where you have to slide down a narrow tunnel like area, but it's only a short distance. You will do a lot of ducking and dodging. The guides are very knowledgeable and the one we had, had an awesome sense of humor. I don't recommend this for people with small children as I have done this tour several times and each time have seen frightened children, or folks struggling to get their children through the tour safely. In my humble opinion, if you have small children, either take them in a front pack or leave them at home for your own enjoyment. It really is best if you have your hands free in case you slip. The cost of the tour is really extremely reasonable and the tour is well worth every dime. I've don't other activities and attractions where you pay much more, but get way less of an experience. The Lewis and Clark Caverns are a must see attraction.