You have to have the basic pass. It also hosts special events which have their own ticket and usually an additional cost. All the ones we've done there were well worth the expense. It is not open all the time, so do check the schedule. There is a special sort of "mini" admission pass you can get now, that I think lets you in just a few buildings instead of everything - a sort of "taste of Colonial Williamsburg" type thing, so if you only want to do a few that might be your best bet.

To the west of Bassett Hall there is a parking lot for patrons of the King's Arms and Shields' Taverns a block away on Duke of Gloucester Street, but I would imagine that one could park there for a visit to Bassett Hall. However, Bassett Hall requires a valid Colonial Williamsburg pass (available for one day up to one full year), and this pass includes the Colonial Williamsburg bus system where the visitors park their cars at the visitors' center and then get around the colonial capital on these buses.