The Premier is a good solid system. I cut my teeth on it as far as Inter-Tel goes. You can do all the programming with Hyperterminal, or Procomm Plus.
Defaulting the system is a good starting point, but you really do need to get yourself a programming manual. The good news is that it's a very basic system and the programming manual for the Premier is an easy read compared to one for say the Axxess.
As for something to watch for, watch your cabling. BTW, the phones require a 3 pair drop and while it sounds like a good idea, don't drop a 4 pair with the idea of being able to have a trunk jack at the desk as well. The AC ring voltage from the trunk ring will choke the station traffic in the shared cable.
What type of VM are you using? Call Express? If so what version.
Lastly, the good news is that Sundance, the sponsor of this board can probably set you up with whatever you need on the Premier at a very reasonable price. I seem to remember Tom mentioning a strong stock in a post not too long ago. Also, a couple of the Inter-Tel Moderators do remote programming, so you can probably hire them if necessary to help you along the way. I'm not sure if RCA is available for it, but I both DnrComm & Bullcube do remote programming and either one of them will know the system very well.