don't know much about the vegas location, but just took my atp at the dallas location.
just learn the little book they give u...and know it cold, you'll be allright.
the instructors want to give u the least amount of time possible in the aircraft, but if you can, tell them u arent ready and they'll let you go up for your second flight. that really helps. After it was all said and done, I got just over 6 hours from ALLATPs. (including checkride) Heck you're paying them 1000 for the rating, you might as well fly all u can and get your money's worth! There were no suprises. Be sure and learn that GPS. One of the 3 guys in my group failed because he couldnt figure out that GPS. Go to Garmin.com and get the GPS simulator and practice. Sorry, I don't know too much about the vegas location, but if it's anything like the DFW location, you'll be happy and no surprises.
sol