Hello!
I looked on the NAR Section Locator map and there appears to be a high-power club in Walla Walla and another in West Richland, both across the state line.
https://www.nar.org/find-a-local-club/nar-map-locator/
They might be worth an email, and they probably have low-power pads too if you’re looking to warm up with something on B or C motors. The West Richland club, Tri-Cities Rocketeers, is also chartered as a Tripoli prefecture.
https://www.tripoli.org/content.aspx?page_id=225&club_id=795696
There are a bunch of people who prefer to build from scratch, sometimes using dedicated rocketry components but at least as often from whatever happens to be available.
Your best bet for professionally-manufactured parts is probably to order online. Estes is still in business after all these years and there are a number of other manufacturers of kits and motors as well. You can get an idea of the variety available on
https://apogeerockets.com, they make their own kits and resell a bunch of third-party stuff. Standouts include Fliskits, North Coast Rocketry, AeroTech (also a motor manufacturer), Klima, U.S. Rockets, Sirius Rocketry, and Aerospace Specialty Products.
Online retailers also tend to have motors, but many organized club launches have an on-site vendor with a trailer full of stuff. Many accept orders for pickup instead of shipping, which is useful for securing the motor you want while avoiding HAZMAT shipping fees and such.
The forum is great, many people have been doing this continuously for decades but many have also had long breaks. One thing that we all agree on is that kid hobbies RULE when you have adult money!