still trying to figure out our plan for when we visit the white house and can't bring our backpack in with us. what if we drive from our hotel in rockville to the metro station in bethesda and leave our car there? then it's only a 15 minute metro ride back to our car vs 30 min back to rockville. but i don't know what the traffic is like from rockville to bethesda at 7am? how long should i expect it to take? what's the best route to get to the metro in bethesda from rockville?