One of your first stops should be The Dalles Dam Visitor Center. Here, you'll be able to find your bearings and get some great ideas before you set out exploring.
This tourist information center is in The Dalles, a place that has lots going for it! Columbia River Gorge National Scenic Area, Columbia Gorge Discovery Center and Wasco County Museum, and The Dalles Dam & Lock are other fine sightseeing opportunities close by when you're all done at The Dalles Dam Visitor Center.