Regarding GCN, don't forget temperature is on your side and it's light by 6.45 now so plan early. Serious study of the POH called for! I'm sorry I forgot to get the parking charges but I doubt it's more than a few $. No landing fee. Worst thing about GCN is the taxis which take ages to come and charge $20 to the rim. Hopefully the Holiday has a pick-up?
I use an ancient Garmin 92 as backup with both an Americas and 'International' database on floppy disk. I swap the databases using the supplied cable when I get back. It's completely adequate for my purpose of:
Verifying VFR navigation
Confirming that you are about to land at the right airport
Giving a 'direct to' if the weather turns grotty
Allowing custom entry of waypoints like the corridors
Giving a position in Lat/Long should you need it in emergency
I'm happy to second what's been said about VGT. They are really helpful there. Best bet for accomodation is the 'Texas' just down the road but if you want to go to the strip they have a huge list of phone nos. and calls are free. You can usually get a better rate by calling a few on the day than booking ahead provided it's not a big convention week.