I picked mine up in Hueneme. It was a piece of cake.
I was in the same spot as you with all the worries about paying sales tax before I got here. I brought two cars with me so that would've been BIG $$ down the drain. I searched the internet and called several times. I got different info each time I called. Until I actually bit the bullet and went to register at the DMV, the lady there informed me about an exlusion I qualified for and .... I didn't pay squat in sales tax here in California. For all the things I can tell you about how Cali sucks, this felt like it made up for all of it.
I'm a Texas resident and they will most definetly charge me sales tax. In fact, even now that I've already registered it stateside with Cali plates and own the title, TEXAS will still want proof of how much sales tax I paid here in Cali and charge me the difference in order to put Texas plates. The best part of the sales tax is that they base it off of the new purchase price and not what it's currently worth.
I think to save $3~4K it would be worth the drive to Montana for you and get some home cooking while you're at it. Welcome back stateside!