yes, key west is small and easily walkable; as previously stated the shopping along duval street is reall not much. the hemingway and audubon houses are close by; the lighthouse is a stroll but worth it if you don't fear heights. there is a nice little aquarium, as i recall, also near the ship. the trolley tour shows you mainly parking lots!!! and a few shotgun houses, a couple of which may have historical value. we got off in mid-trip and walked back to our inn. the old cemetery, also a decent walk from the ship, is fascinating; some names you may know if you are from the south or florida, in particular. there is also a house near the cemetery with an unusual wall made of bottles. otherwise, no big deal. i'd never pay again for a tour; just get a map and do it yourselves. i don't think key west is very dangerous to walk around. ps: there are no real beaches since kw is surrounded by reefs. and they(the beaches, not the reefs
) are infested with vendors. hope this is helpful, but, again, it is only a limited opinion. have a great cruise.