I have been to Bend to twice for a beercation, have to say a paid beer tour would be a waste of money. 1/2 of the breweries are with in blocks of each other, a few more are just a short walk. Their are only a couple that would require a drive. As pointed out earlier check Bend Ale Trail, they even have an app for smart phones that is pretty handy. My favorites Deschutes (both the tour at the brewery and the public house), Bend Brew Co., Boneyard, and Crux (this requires a short drive). 95% of the places made solid beer only disliked maybe two (yep we hit them all).
I also agree on Portland. Great walking city. But here a beer tour would be so bad to get you started. But if you see if you can get one that will include some breweries outside the City. Hood River has Double Mountain and Full Sail both of which had great beer.
Good luck and have an amazing trip.