This isn’t practicable every time, but one solution is to have Dopefests at places besides restaurants, such as people’s houses. (We do that a lot up here in the Mid-Atlantic area. Gives people a lot more freedom to circulate and stuff.) One thing I want to do sometime in summer is reserve a pavilion at a local park for a Dopefest.
That would be good or just rent a conference room out in a hotel. Keep everyone in there and circulating.