1 PM in Rockville might work for me as well. I was planning to leave DC at noon, so we could probably meet where convenient.
How fast are you guys willing to drive on the highways? I typically try to avoid the reckless driving limit, so I try to keep it within 10-15 (sometimes a little over

) of the posted highway speeds.
Also, which route are you planning on taking?
Finally, which hotel is everyone using?