You live in Oregon.... Half of us are friendly or non-committal, the other half are On the verge of losing their bladder control at the sight.... Or Non-Committal.
Land of the "Man with a gun" police response to a Gun store.
"Police responded in force to reports of a man with a gun in Southeast Portland late Monday -- only to find a confused customer and staff at a gun store"
http://www.oregonlive.com/portland/index.ssf/2010/09/post_38.html
It's not Illegal, but get a Soft case, or use a bedsheet and a bungee cord if you're transporting arms to and fro. Never know when a load might shift in your trunk, or you'll catch a tree root with your toe, and the case takes the damage, not the gun.
I also drive a station wagon, so there is no real concealed area for my rifles, Driving a glass bubble with loose guns flopping around in the trunk for the world to look at like a half-baked museum case seems... wrong to me.
Then get your CHL , Not a bad card to have even if you don't intend to CCW. Especially in good 'ol weird Oregon.
Sometimes case-free travel is unavoidable, but as long as you aren't pointing it at anyone ( and they don't lie about you doing so when the police come and point out you've broken no law otherwise) you should be eventually left alone.
My concern is hand-carrying to and fro, When I OC it's clearly in a holster. Some really sensitive soul might claim you brandished your weapon, but I've watched people carry long guns onto the Light rail system from the gun show. Just watch your muzzle sweep.