I get don't get why people feel the need to be "in the closet" about their enthsiasum. How many people outside of the coaster community know about the sterotypical geeky enthusiast?
So Blueman, go tell your freinds that you are into coasters and maybe they'll be into coasters as much as you. Wouldn't it be fun to go to tons of parks with them?
Hotels in Washington D.C tend to be either really fancy or really ghetto. I would recomend saying outside DC and take the Subway in to DC. When my family went to DC a couple of years ago, we stayed at a hotel (there are several hotels) in Columbia, MD and we drove to a Subway station in Greenbelt (I think).