Some rivers will have early spring chinook and still have good steelhead prospects. As well Sturgeon should be full swing.
Contact :
Amerman Fishing Service
Scott Amerman, Grant Scheele, or Ian Premo
http://www.ifish.net/amermanfishing.html
Grant Scheele 541-990-6538
Scott Amerman 503-392-9468 or 503-801-3938
Ian Premo 503-752-3753
http://www.premofishing.com/
These guys are the best around for Spring Chinook and Steelhead fishing. They wrote the book on egg and bobber river/tide water chinook fishing and, springers (chinook) cannot be beat for flavor. Amerman team will fish you out of a drift boat or small flat-bottom sled on some of the most senic rivers in Oregon - and these guys have the cured eggs like no other. Scott and Grant will fish coastal rivers and valley rivers south of Portland. Ian will be fishing rivers around Portland area. Go with who ever thinks the fishing will be best for your time of the season. Definately mention my name to help get on to their calendar as they reserve most of their availability for returning clients - Calvin Harmon.
see below pic for a personal best for steelhead with Grant Scheele from last thursday.
Another guide I really like is:
Nalu Guide Service - Mike Jeppersen (503) 848-6020
http://nalucharters.com/index.html
Mike is an offshore guide who specializes in Portland area sturgeon fishing during the winter. Give him a call to confirm he's not out to the ocean by end of march. Mike fishes out of 28ft Grady White.
David Johnson will likely be fishing Sturgeon at that time as well. He is good guide but not as good as Amerman on spring chinook and steelhead. Different fishery and style than Amermans team. Mostly trolling in 6-man open sled. David is good steelhead guide if the rivers he fishes are still producing good numbers - drift boat fishery as well. That Sturgeon fishing is good fun as well - generally lots of bigger fish that put up a good fight that time of the year.
My vote is for river drift boat or drifting in flat bottom sled with Amermans - very peaceful setting and you have a rod in you hand working the holes and slots as you side drift along with the current.
Good luck
Nice Winter Steelhead: Grant Scheele guiding but not pic'd
Perspective: My buddy and I are both 6'1 275lbs each - big fish!