Vehicle registration across states

Not sure where to post this question - but I am in a unique situation.

I am buying a car while living in MD, then taking it on a road trip before moving to WA in early April. That means I will have the car over 30 days (but not by much) before needing to switch to WA tags, and MD only seems to offer 30 day temporary tags (60 day tags only apply if you buy through a dealer). So I'm wondering which of the following can I do, and which makes the most sense:

1) Get regular MD tags. Go to WA, then get regular WA tags. (Probably the most expensive option)
2) (If they even have this) Get 60 day tags from some state that offers it remotely, then drive to WA for my regular tags.
3) Let my car sit in a garage for 2 weeks or so until I can get 30 day MD tags. Drive to WA and get regular WA tags.

I just don't really know what the rules are for vehicle registration - if you can have gaps where it isn't registered so long as you don't drive it, if you can use your temp tags to drive across states at all, or if you can get temp tags without physically going to a DMV or being a resident in that state.

Keep MD license + Tags for a year.

Before you plan on leaving MD tags on the car for a year - better make sure WA isn't going to charge you sales tax again on the car's book value when you re-register it. My state does that, and, the local and state police watch for people running out-of -state tags for an excessive amount of time. How - they watch school parking lots in the morning and see if parents droppping off kids are running out-of-state tags.

Regards:
Oldengineer

Well, no kids so that shouldn't be a problem. Unless they monitor the parking lot at work, then I'm out of luck...:uhoh: