The Marriott Long Wharf isn't an awful choice, but it wouldn't be my first choice, especially in late October. That Marriott has great access to the Rose Kennedy Greenway, any types of harbor cruises, the North End, and the Quincy Market area. However, late October isn't a great time for harbor cruises (especially for people from Florida), and most of Boston's best attractions are harder to reach from the Waterfront area.
Most people would be much happier with a hotel in the Back Bay/Public Garden area -- the Four Seasons or Taj, for example if budget allows. Easy walking distance to Beacon Hill, Newbury Street shopping, Freedom Trail, Boston Common/Boston Public Garden, South End restaurants, and the theatre district.
Weather in late October might find a lovely day with temps in the very low 60s, or a nasty early taste of whats-to-come with a howling wind and temps in the chilly 40s. The wise traveler is prepared for either.