We started using Greenbelt National Park back in the 70's. We have been there about 5 times through out the years, the last being about 3 years ago. The subway station is close by and if you travel after 9 am and return after 7 pm you can take your bikes with you. The last time we were there the national parks service had a bicycle tour of about 4 miles that was very interesting. We will be back there in June or July.