You could just do what I did. Get in it and drive, and keep your fingers crossed. the likelyhood of getting pulled over on the interstate is small. I drove my skoolie 2200 miles with its original school bus plates on it and no one gave it a second look. (well, actually, a couple of state police did look, but I guess they figured it wasn't worth the trouble to stop me)
Also, some states give you a "grace period" after a new purchase to get the vehicle to its new hjome before registering it.
In indiana it is acceptable to use plates from any vehicle currently registered to you to transport a newly purchased vehicle.