Agents may help you if you rent a place the agent found on the mls, because then the agent will get some kind of a commission from the rental owner. But doing this will limit your search. Others have posted on helpful websites, another one to use is: http://www.housingsearchnw.org.
I appreciate your situation and am a avid traveler and I will guide you at no cost. I can help direct you and give you some ideas. No expense. When I was traveling for 2 years, people were so generous to me and helping you will help me pay it forward. My email is firstname.lastname@example.org.
Yes, there are agents like me who help because we build our business on relationships and referrals. The fee is paid by the owner on listed properties, so there is normally no fee to you.
There are good rental properties in the Northwest mls, but supply is VERY limited. I am happy to help you search the mls, but at the same time I recommend you stay on top of Craig's list and other public rental sites. The last time I checked vacancy in Seattle, it was about 4%! You can also set up a rental search at my web site, http://www.buyandsellseattlerealestate.com .