I would have prefered a direct route from the marina to the city. The "tour" aspect without narrative made the trip longer than necessary as there isn't much to see from Charleston Harbor Marina to the location near the aquarium which was our landing point.
I do realize some may favor the round about route but we were hungry and just wanted to get across to the restaurants. Also when traveling from the marina to the Charleston - the drop off point at the aquarium is almost a mile away from any of the shops, restaurants etc. No taxi's were available so it is a hike to get to where you want to go. We didn't mind the walk even though it was a hot day but some may especially the elderly.
The round trip aspect didn't come into play for us as we weren't inclined to venture back to the pick up location even though we were have preferred to do so in order to change for dinner. But it is simply not convenient. Also last pickup was 7:30pm which on a Saturday night isn't practical for most.