You'll enjoy the trip.

In Reno, I like the Peppermill, though the casino has quite a bit a retro neon. It's not downtown though. For downtown, Harrah's has a nice property, though spread out. To be in the middle of downtown (right at the Reno Arch), the Eldorado or Silver Legacy are nice too.

In Tahoe, it's hard to beat any of the major properties at stateline, next to California border. Check out Harrah's-Tahoe, or Harveys. I personally have not stayed at Montbleu, but hear good things about it too.

For a few unusual things to do (if you like these sorts of things) --
The V&T (Virginia & Truckee) Railroad runs from Carson City up to Virginia City. Virginia City is an an old silver mining town, but now caters to tourists.
On the north shore of Tahoe, the Cal-Neva lodge should be re-opening by now (I think, but check). Has historic interest, from the Sinatra days, etc. if you're into historic casino stuff.
Also on the north shore is a tour of the historic Thunderbird Lodge. Read about it at the link, below. If you go, get tickets early, because tours will sell out for the limited number of tickets available.
http://www.thunderbirdlodge.org/