I would suggest calling a taxi - Mears would proabably cost alot more then a taxi would. The taxi would also get you there quicker then Mears because if Mears has more then one stop you may not be the first stop.
Yes, DC is top-notch! Been there several times. Take a Taxi!!! Avoid Mears or any type of shuttle service. You should defintely arrive at DC 30 minutes or more prior to opening, so you get first choice of your swim time.
My daughter and I are planning to do the dolphin...grandpa to entetain himself with the rays and dad missing the whole thing! Just saw a video from a friend's trip and it looks awesome. Thanks again for the info re: trans to dc from contemproary. All advice eagerly accepted.