Regardless of the beer post back on Prague. Its on our short list. The conversion rate and history makes it look like a great cheapish trip.
Let us know if theres enough to do for a week or will a couple days see it all without venturing further out on a train or bus....thanks
As mentioned, the Prague Beer Museum locations are good. If you're going to the castle, a walk to Klášterní pivovar Strahov is definitely worthwhile (a bit touristy, but great setting and tasty beers).
There are also a number of more modern (geeky) places on/around Vinohradska (the main road east of the train station, away from the big tourist traffic). Beergeek Bar is an American-style taproom on Vinohradska with an excellent taplist (http://beergeek.cz/#tap). Another nice one on Vinohradska is Dno Pytle. While you're in the area Vinohradsky Pivovar (http://www.vinohradskypivovar.cz) is a brewpub with 4-5 own taps and excellent food. 20 PIP is also great (good mix between locals and import: https://untappd.com/v/gastropub-20-pip/3774123).
If you are there for more than a couple of days, make a day trip to Plzen (Pilsen). It's only a 1h30 train ride away and the tour at the Pilsner Urquell Brewery is really good.
You need to drink Pilsner Urquell in a tankova. It is a completely different beer from what you'll get in the US. The pubs called Lokal handle the beer very well.
Beer Museum is owned by an expat from LA, FWIW.
Zly Casy is a bit out of the way, but it is the most authentic way to drink craft beer in Prague. A bit easier to find and a bit more Americanizes are the Beer Geek Bar and the Beer Geek Bottleshop, both in Vinohrady very near the Jiriho z Podebrad metro stop.
U Zlateho Tygra (The Golden Tiger) is abolutely swimming in history. You may have a hard time getting a seat.
U kunstatu was really cool, Beer Geek bar was also cool. Fat Cat was good. Prague is amazing. My daughter did a semester abroad there last year and I went and spent 10 days there over thanksgiving. The Christmas markets are really cool. It is also cheap. I think the most expensive meal for the two of us with drinks was like $60 usd.