Gary's link is bang on.
I own a Side X Side ( UTV) and last year my Cuz from Oregon came up to go riding with us. All they needed was to insure they had their registration papers from the State of Oregon with them.
Read the info in the link (s) as I have read the enter link since last spring things could have changed. But it was no big deal.
Lots of places you cam ride up here but there are a lot of places you can't, so make sure you know before you unload.
Most towns and villages have ATV clubs that you can find links to and or contact info on the internet. It wouldn't hurt to look those guys up when you want to go for a ride. Lot of guys around here I k ow will go out with people from out of town to show them around if they are available.
Have fun, there are a lot of great rides up here.
Soup
2018 Northern Lite 8-11 EX Dry Bath
2017 Sierra SLE, 3500 HD / 4x4 / Duramax with a 6 speed Allison Trans
Torklift Super Hitch 20K, 48" Super Truss, front and rear frame mounted tie downs
Fast Gun Long Range SS Turnbuckles, Fast Gun locks