About the only spares I can think of would be another prop or two and at least one more battery pack. I'm not sure what prop is recommended for the EZ 400 Glider, but I'm using an 11x7 APC Electric prop on the Pleaser 400.
Check around for pricing on battery packs. One place to look is www.eflightpacks.com
They have a good rep here and the prices and delivery are real good too. This way you can have one pack flying and the other one on charge.
Another thing to consider is a computer raido. I've got a Flash 5 from Hitec and love it. If you got it just for the 5 model memory you couldn't go wrong. Servocity would be a good place to begin looking.
There are a multitude of chargers for you to ponder over. If you think you are going to be in this for the long haul you might want to think about getting the best you can afford. "Buy cheap, buy twice" is a favorite piece of advise around here. Do a search on chargers and you'll have more than enough reading for a while.
Our club has two fields, and the closest one to your location is the one that is fairly close to Waterloo Village if you're familiar with that historic site in Warren County.