The only places that are "guarded" are the parks. Anyone can walk into any resort and look around. Obviously you can't go to a different resort to use their pools (the
one exception to this is DVC members can pool hop at
select resorts).
Here are some links that talk about what there is to do at the Boardwalk.
http://allears.net/btp/brdwlk.htm
http://www.wdwinfo.com/wdwinfo/resorts/boardsrecreation.htm
If you're driving the Boardwalk, the parking lot is guarded and reserved for resort guests only. There is overflow parking across the street near the Hess gas station. Or if you want to use Valet parking, you need to go to the parking attendant and they should let you in so you can drive up to the main hotel entrance to get a valet.