You've got an air station in Astoria, another in North Bend, and one helo from North Bend based in Newport (although soon to be closed Dec. 15th).
I would imagine that many rescues close to shore would be coordinated between the USCG and local fire departments / fire districts on VHF marine channels or VHF fire channels. As far as Milair comms go, it probably wouldn't hurt to plug in the various nationwide USCG UHF frequencies and see what pops up. Plus, the CG supposedly has their new(er) digital VHF channels in operation on the OR coast.
But like Mike said, with just an HT antenna, your range is going to be pretty much limited to line of sight.