For a bike shop, I would suggest Bike Gallery: 12345 SW Canyon Rd Beaverton, Oregon 97005

As far as a route, riding up to the zoo and back would give you a decent ride with some climbing. I would suggest using the cycle route option on google maps as mtnbud suggested. If you do that, 6 or so miles of your round trip will be on a bike/walking path along highway 26. That is the only route I know of, because when ever I go on a long ride, I get the heck out of Beaverton!

also, you can head west on Baseline out near the Hillsboro airport. I have gone as far as that, can't tell about what is beyond.