Train
We use the Metro every time we go into DC! It's really great and pretty clean compared to other trains Quinn has been on. They also have an app, which doesn't have a lot of good reviews but you can always try your luck if that's your jam. In order to get to the venue, you are going to want to either get a ride to or park at a ORANGE, BLUE, or SILVER line metro station and get off at ROSSLYN metro station. ORANGE line goes from the Vienna/Fairfax to New Carrollton. BLUE line goes from Franconia-Springfield to Largo Town Center. SILVER line goes from Wiehle-Reston East to Largo Town Center. All three of these lines take you to the ROSSLYN stop. From there it is a 30 minute walk (roughly 1.2 miles) or a 5 minute drive. Rosslyn DOES NOT have parking reserved for Metro riders.
Hotel
I was looking and this one was like $85/night and prices might fluctuate over time!