Suitland is tough because you have to cross two rivers, no way around it. What about going part way by Metro and the rest by bike? By Metro you would take the yellow line to L'Enfant Plaza and switch to the green line to Suitland. Either half of that is a do-able bike ride, and Metro alleges travel times of 16 and 17 minutes for the two legs (but don't believe them). If you are riding outside of rush hour (7-10AM, 4-7PM), you can take your bike on the Metro -- or you can take a folder anytime!