We are stay in Legion Lake in Custer Park and would like to visit Mt. Rushmore for daytime and evening. We are a group of 8 adults including elderly parents. Would it be doable to visit Mt. Rushmore first, then head to Deadwood and Spearfish Canyon and come back down to Mt Rushmore for the eve show? As long as we take breaks, my parents are good travelers. Or is it better to do eve program on a different evening? How worth is the additional hour, each way, side trip from Spearfish to Devils Tower? We are in Black Hills area for 5 days.