There are more impressive caves in the US but because of the included boat ride and lake scenery, Shasta caverns is a good overall package. The tour is 2hrs total and requires going up and down 600+ steps. 5min down to ferry (pre tour start), 13 min ferry ride, 12 min bus ride to cave entrance, 40 min inside cave, 10 min walk down from cave exit to cave entrance, 12 min bus ride back down, 13 min ferry return, 10 min walk back up to parking and 10 min wasted waiting to get inside the cave and for the return ferry. Walking back up to the parking lot is the only unpleasant part and they did offer a bus but its not standard so most folks don't take it. The cave is a typical limestone cave with the best formations in the last room. Best views of Lake Shasta are from the bus (from right side bus windows going up near the bare spot and post cave exit on the walk down).
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