So I used to live and work in DC and moved back to the Philly area for family reasons, and I've seen my friends from my time in DC slowly move away for a lot of the reasons you cited. I live in the southern NJ burbs near 295, and I think you could find something like what you want here, especially around Collingwood or Haddon Heights. There's a fair amount of nerd stuff this side of the bridge, my husband and I are partial to Tiki Tiki Board Games in Woodbury, who has a whole Nerd Mall setup. If you want to research nerd culture around here, you could always come up for Pax Unplugged at the convention center the first weekend of December.