Sorry - this is going to be long. I have a lot to say!!
Supershuttle is an airport transfer service. They are vans - the one we were in only held 8 people and I don't know if they have bigger ones. It wasn't cheap (about $40 per person round trip.) Yes, they do take you right to your hotel. Like I said, next time we will take the train. There is a commuter rail stop right at the airport. The website is
http://www.mtamaryland.com/. That takes you to Union Station, which by the way is a FANTASTIC place to eat - the food court on the bottom level is to die for - tons of variety. We ate there every day. And Union Station is also a Metro stop.
As far as safety, if you stick to the tourist sections and the hotels people are recommending, you'll be fine. We never had a problem and we walked and metro'd all over, but nothing off the beaten path.
We loved the neighborhood for the Holiday Inn. It's closest the Air and Space, but really you can walk to anything on the Mall very easily. Since that was where we spent the bulk of our time, it was perfect for us. As someone said, DC is a walking city, so you're going to walk a lot no matter what, and this is a great location.
We did not go to the pool, so I can't give you info on that. The lobby does have a bunch of couches and chairs and is a very nice room, so you could possibly hang out there in the evening. There is also a full service restaurant (Smithson's) which was just okay, and a bar and grille that we didn't go to. There is also a quick-service eatery.
"Smithsonian" is the 'official' metro stop for all the Smithsonians, but the closest metro to the Air and Space is actually the "L'Enfant Plaza" stop, which will bring you to the Air and Space via the "back door", not the door on the mall.
One thing to make sure you know about the Holocaust Museum - it's free, but they have what is called Timed-entry tickets. Meaning, you have to go there first thing in the morning and get your tickets, which depending on the lines may be for later in the day. If you just show up in the afternoon, the tickets will all be given out for the day and you won't get in. There is an exhibit you don't need tickets for, but it is very small compared to the whole museum. If you don't want to go the museum in the morning, you can get tickets ahead of time at
www.tickets.com. The tickets are free, but you'll pay a couple dollars service fee.
Timed entry tickets are very popular in DC. You'll also find them at the Bureau of Engraving and Printing, The American Indian Museum of the Smithsonian, The Washington Monument, and the Spy Museum (which is not free, the others are). It requires a bit of advanced planning to make sure you get to see things.
We love the Tourmobile. We use it every trip. It really is the easiest way to see the monuments, because there aren't any metro stops nearby them and it would require a hefty walk otherwise. The website is
www.tourmobile.com . The tickets are $20 for adults, $10 for kids and if you bought a 2-day ticket (must be used 2 consecutive days) it's $30 and $15. There are a couple other tourbus companies in DC (Like Red line and Gray line) but we tried one once and was disappointed. Tourmobile is run by the National Park Service, so in my opinion, the narration is a notch above and it's cheaper to boot. The other ones do go to different stops though.
General tips:
www.washington.org is a great resource for planning attractions.
The website for the metro is
www.metroopensdoors.com - print out a map before you go and generally familiarize yourself with the layout.
And eat at Union Station - you won't be disappointed!!