I’ve done this commute for the past year or so, commuting from Columbia Heights to the Hopkins campus in Baltimore. I mostly do metro>MARC>shuttle in Baltimore, and only drive if I have to be up there late or do errands. Best case scenario, if I take an express MARC train and the timing for the shuttle works out, it’s about an hour and 15 minutes door to door. Worst case scenario (slow MARC train, waiting for metro and shuttle), it’s closer to two hours. Driving is about an hour door to door – even at rush hour the traffic doesn’t really get bad until you are right in Baltimore.
I work from home a lot, so I generally only do this commute maybe three times per week, and that doesn’t bother me – I get a lot of work done on the train. But there were a few months where I had to commute 5 days per week, and that was pretty draining. I think it would be pretty difficult to do if you had a strict, 5-day 9-5 type job. If you have some flexibility (could telecommute or have a lot of control about when you arrive and leave work) it’s not too bad.