If the circulator is running, take it. If it isn't, take the Metro Green line to the red line. I guarantee you it won't be a half hour wait for the Green line. You can wait a while at the transfer point for the Red line though, but like I said, I make it from the Park to Shady Grove in an hour.
If you are driving to get to the Metro, consider driving to one of the Green Line stations with parking. If you are really in PA, and coming to, say, Shady Grove off 270, drive another half hour to the Green Line station at Greenbelt. I'll bet you save all the time you would have spent transferring, etc.
But if there's more than three people in the car, I'd just drive all the way in and park for $20.
No one answers for the Circulator, and the mailbox is full - it transfers you to Metro. The first time they just hung up on me randomly, the second time they said that the Circulator won't run on weekends - really useful, jerks.
The only way to get back to the red would be to take the Navy Yard train. Fun stuff. She said it's every 12-15 minutes, and then the Red is every 20 I think.