My husband and I are on the same cruise and have been planning to get to the Ferry on our own and go to the Baths. We think it is possible. Leave ship at 12 (or as soon as possible), walk 12 mins to Ferry, get on 12:30 ferry, arrive 1pm, take taxi (10mins), Probably be down to Baths by 1:30…and then take 5pm ferry back. I think that leaves about 3 hours of exploring the Baths and beach which is good.