For experiences, please see the many trip reports in this section. Everybody has a different experience.
Flying from Buffalo will be cheaper then flying from TO, but leave extra time to cross at the border. In pretty sure that all the carriers have a direct flight to Vegas, but those flights are limited so you should book ASAP.
As for hotels, you have many choices. You need to decide WHERE you want to play the most a book a hotel accordingly. Almost every casino has a poker room and the most common game is 1/2 NL. If you're not sure
www.allvegaspoker.com is a great site for a Vegas rookie. Same for tournaments, figure out your but-ins and find one that looks good. I prefer the $125 at Binnions and Aria.
I've heard that the Nugget is nice and reasonably affordable, but be warned that it's WAY off the Strip in the area of Vegas called Downtown. There are a few casinos in that neighborhood (Binnions, 4 Queens, Freemont, El Cortez and more) but if you're planing on playing a MGM or Aria, expect to take a cab or the bus. Its pretty far of a walk that goes through some shady spots if town.
Im not even going to talk about restaurants except to say that you will not starve. There are hundreds of places for every budget and culinary preferences.