I'm a little late on this, apologies.
Did you ever decide to do anything with what I PM'd you, with Oregon Country? I think that would be a solid base for you to start off of.
You said that you want German tech and that implies why you want to side with the Axis. That doesn't have to be the case though. As apdsmith said, you're on a land border with the US, and that is a no-no. They'll have defeated your nation before you even utter out your declaration of war on them.
Before you determine what side you are on, you need to figure out what of German tech you want. So what do you want? Do you want the technology and building methods or do you want the actual equipment, like Tigers, Panzers, etc? (because you're not likely to get that anyways)
About that, im still working on the layout of that, main german vehicles that were given to Cascordia was panzer 4's and luchs aswell as some half tracks.