Without pictures or without a precise length, it is hard to say for sure but from your description, that sounds like it could be a Westerly or a Signet.
Personally, I have bever been a fan of bilge keel boats, (poor sailing ability and the problem of how to free them when they run aground) or Westerly's for that matter (sloppy build quality and mediocre sailing ability), but for some reason I have always liked the Signet (19'-10" LOA) which I had a chance to sail briefly when I lived in Florida. (Here are a couple examples 20' Signet Sailboat
and Signet 20 Twin Keel Sailboat Project
If the boat is a Signet and were in near perfect condition and capable of sailing she would probably be worth somewhere around $3000-3500. As you describe her she is worth something well under $2000 and may have little or no value is she does not have good sails, interior furnishings, and an outboard. There was a pretty nice one for sale in Annapolis on a trailer which they were asking $2K for a few years back.