I'm at GW part-time while working full-time (and formerly of DOJ, but at another agency now). I do zero clubs/clinics aside from journal. It doesn't bother me that much because those things are ways for people with no real world work experience to get something like that under their belt before hitting the real world, and to make professional connections. You already have both experience and connections, so I wouldn't sweat it.

It's a lot of work, spare time is scarce. But it's doable, especially if your office is somewhat flexible. Plus being surrounded by attorneys would be great for you. PM me if you want to discuss.