to stay in my spare bedroom.

...also one of the more saturated spots probably (just like Midtown) but for good reason. Another option would be the Georgetown-Foggy Bottom area.

Crystal City, which is just across the river in Virginia, has many hotels with less expensive room rates, especially when compared to DuPont Circle. There is Metro access and parking is not hard to find.  

Good luck, Ms. Courtney, and I hope to meet you when you visit D.C.

I'm not sure why Dupont Circle gets so many responses to this question, which is asked often on this board (no slight intended to you, it's a good question). There are decent 4-star hotels throughout Downtown DC that are within 4-5 blocks of the red/orange/blue/yellow lines. Any of these will suit your purposes. If you like dining in good restaurants, closer to Penn Quarter/Verizon Center/Chinatown may make you happier than Dupont Circle.

Tysons is popular with providers because so many people work there. The trouble with Tysons is horrendous traffic, so be prepared for some dates to be late. The metro now goes there, but not in a way that I think would improve the convenience for providers or hobbyists.

Also beware that if you want to explore outside your hotel during your stay, Tysons and Crystal City have little to offer outside of shopping malls. Downtown DC / Dupont are much better for that.

Good luck.

what you need to understand about DC is that some like to drive and some like to ride.....

so if you choose a location with metro access you are often choosing a location without good parking for the drive and park guys.....

but if you choose a good drive and park location often metro access is not convenient....

many seem to like to split their stay in town between locations optimized for each...