It seems there are several times and places to get to the Fort. Any ideas aas to wehat is best? We have one person who isn't good on stairs. Is this a problem? How long will it take to go through the fort? We also plan on flying into Charleston, renting a car, then when we are done, we want to drive across state to Greenville, where we will be visiting relatives. After that we will drive our rental car to Charlotte, NC, and fly out to Kansas City. Do you see any problems doing that?