Highway 101 runs along the entire Oregon coast, from Washington State to California. There are state parks worth visiting along the entire stretch. Especially scenic are the stretches between Cannon Beach and Manzanita on the North Coast, and near Coos Bay on the South Coast (especially Shore Acres State Park).
If you’re also interested in history, Lewis and Clark National Historic Park on the North Coast is fantastic, and also includes beautiful scenery. Astoria, Oregon, on the very NW tip of the state is a great place to start exploring the coast.
Closer to Portland, you might want to plan to visit Oregon’s wine country for rolling hills, beautiful farm land, and of course picturesque wineries! Learn more here.
Also not far from Portland, the Columbia River Gorge has some of the most impressive landscapes in the state.