Here's my picks from your list, given an 80mm aperture. If possible, I'd suggest throwing in some decent binoculars too.
Easy:
M31 Andromeda (unsure, better with binoculars, i've never been able to spot it in a refractor due to too much magnification and too little aperture)
Perseus Double Cluster (must see, easy find)
M13 & many other Messier clusters in that region
Challenge:
M81 & M82 (low elevation on that date/time, better at 3am on the am of the 15th)
M57 Ring Nebula (easy to locate, with enough aperture)
M27 Dumbell Nebula (aperture)
You can't forget Vega & Polaris while you are there
With a 30 second exposure you are likely to see most of the objects in the above lists.
According to my quick checks via Cartes du Ciel, with the observatory set for Phoenix, moon rise is not until after midnight on the morning of the 12th, and around 3:45am on the am of the 15th, so you will likely have more observing time than you had planned.
You'll likely be getting down close to freezing temperatures that time of year, so pack some warm stuff.
Enjoy your trip
