Glad to help out, Jen.

You are about 10 - 12 blocks from the west end of the Mall (Lincoln Memorial end), so you'll probably want to take Metro. Your hotel is about 4 blocks from the station at Dupont Circle (Red Line) and 4 blocks from the station at Foggy Bottom (Blue and Orange Lines). You can choose which station is better depending on your destination. See the Metro website for info on routes, fares, times, etc. www.wmata.com

The various hop on/hop off buses (which I think is the "trolley" you are talking about) are popular with tourists for the "Monuments by Moonlight" tours. But for daytime sightseeing, they are good only if you plan to stay on for an entire loop before you get off for any sightseeing because you often have to wait a long time to get another bus. They are also an expensive and inefficient way to get around to specific sites. Use Metro if you just want to go to the zoo or to the Smithsonian museums.

Finally, on the day that you go to the Natural History Museum, I'd recommend taking your lunch break elsewhere. You could go next door to the Sculpture Garden which has a cafe (although I've never eaten there). The kids would probably enjoy some of the sculptures there--weird house, giant eraser, etc. Or, I can highly recommend the Cascades Cafe at the National Gallery of Art. It's a food court with a lot of choices and the food is fresh and tasty--much better than your average museum food. Also, the kids will probably like the indoor waterfall (cascade) and the art installation that is a moving sidewalk surrounded by blinking colored lights. Both are right next to the cafe.

That's my favorite sculpture garden anywhere - and I'm no kid! Another very good food couture is the one at the Museum of the American Indian.

If you are going to be at Hershey and then going to the beach, I'm sure there are closer beaches in New Jersey, for example, that have boardwalks. Going all the way back down to Ocean City, MD, seems like a real waste of time.

I think I might do DC first, then Hershey, then the beach somewhere and then spend a few days in Baltimore before flying home.

Jen- I'm curious about why you want to bypass so many other beach towns (OC, NJ; Cape May, Rehobeth, Bethany) to go all the way to OC, Maryland. I grew up going there every summer, worked there one summer in college, and my parents retired there, but it is definitely a tacky beach town with no charm or scenery. Of course, hundreds of thousands of people love it, I know, but in my opinion it isn't the best of the options, esp with a long drive taking up your fun and relaxation time. You might post here in another thread asking people to weigh in on and give descriptions of the various beach towns because they each have their own flavor.

July is high season, so it will be crowded and I recommend booking a room or condo (condos are everywhere in OC but usually require a week rental Saturday to Saturday but you may find one that would do a few nights) ahead of time.

If your kids enjoy putt-putt golf, go-karts, carnival-style amusement park rides and games, tacky beachwear shops, and jumping the waves and digging in the sand, then they will love OC. I know as a kid I sure did. As an adult, I find it too built up, crowded, traffic-filled, etc....but my parents are there so I go to see them.

You could get more beach time and the boardwalk experience in one of the more northern towns on your route, with more charm and a shorter drive from Hershey. Plan to add at least an hour or two to what mapquest or google tells you because of traffic and crowds. If you take the direct route from Hershey to OC, Maryland, you will be on mostly farm roads in Delaware. I think it's a lovely drive but as a kid I was so bored I used to count the telephone poles.

Just my two cents on the beach planning!