Great! What a small world; I am in Seattle. And I know all the coaches at both of those schools.
And don't worry about the redundancy-- I was giving you a hard time
Here's what I think you should do:
1. Call the coaches at both of those schools. They can give you specific info on transfering and rowing for them (PM me if you want names and phone numbers; they aren't hard to find online, though). Also, if you go to their web sites, they'll have an online recruiting form that you can fill out. Western Washington is DII, and UW is DI. Both crews are consistently in the top 5 in the country in their respective divisions. UW rowing is as close to professional as you'll get; WWU is slightly less so mainly because of the NCAA restrictions on DII athletics. WWU will drool over a 6' tall transfer.
2. If it were me, I'd tell you just to work on your general fitness. I would *not* erg at all, because you risk doing it poorly and your new coaches would have to break ingrained habits. If you can find someone to teach you how to do it, great (not likely, in Walla Walla). Otherwise, run, do stairs, bike, and lift. As far as lifting, I'd work on core strength (planks!) and basic movements: push ups, chin ups, lunges, squats. Get really, really good at those technically, and you'll eventually impress a coach with your knowledge and kinesthetic awareness. You can also look at my log for more workouts. Like I mentioned in the other post, I have no idea how to link it.
3. As soon -- like, the minute-- as you know where you are going, call the athletics department and ask to speak to the Senior Women's Administrator. Let her know that you are transfering and that you need to complete the NCAA Clearinghouse. This is a really important step. Your (new) coach will also tell you this, but you can impress him or her with your eagerness to get started, if you take the initiative.
4. Have a lot of confidence. Collegiate rowing (like any other college sport) is really demanding, but incredibly rewarding and a lot of fun. One thing that is great about college rowing is that coaches do not expect you to know much, if anything, about rowing when you start. All newcomers join a novice team and compete separately from "varsity". A novice team might consist of 10 experienced high school rowers (who might move to varsity immediately) and about 60 walk-ons with no experience.
5. If you ever make it to Seattle and want to ride in a launch to watch some rowing, PM me and we can arrange for you to come to one of my practices, if you're interested. Or, if you can, come to town next weekend-- there is a HUGE race with local crews, hosted by UW. WWU will be there as well, and if you time it right you might be able to speak with the coaches face-to-face.
GOOD LUCK!