You are both in one of the best areas of the country to find a used TC, but any from the PNW need to be checked closely for any water leakage damage, due to the climate. The mountain west is another good place to look, Colorado, Idaho, Montana, etc.
I found my current TC, by just doing a google search for the make and model I was wanting. My plan had been to go to Colorado to buy one, or to Texas, but this one popped up on a RV dealer's lot as a consignment unit. Make my deal over the phone, subject to inspection and my final approval. He faxed me the paperwork, I sign it as did the dealer and I gave him a $500 credit card deposit. My previous TC, I found the same way, over the Internet, in eastern Tennessee. Purchased it the same way.
TCs are not all that popular here in the SE part of the US, so not much of a selection but get out west and it seems about every third unit I see on the highways is a TC.
Check out some of the large listing groups, if for nothing else to get a feel for what others are asking for TCs that might be of interest to you. Again just google something like "used truck campers for sale" and you will find many pages of reading material most of the time.