The Santiam River is a great place to learn how to whitewater kayak. This will be my second year of kayaking, and I learned on the Santiam. There are many trips on the river that are great. The one I like to travel best is from a park called Packsaddle County Park, and I take out at the main bridge in the town of Mill City. At the bridge there is a dam that is a class 3 as well, scout it before heading up to the put in. We traveled it on the far left side (left from being on the river). The trip is about 6 miles long and has a class 3 about 3/4 of the way through. The rapids are great, mostly 2 and 2+ depending on the level. Further down the river the water gets easier. Another good put in is at Fishermen's Bend Park, and you take out at the bridge at Mehama. It is about the same distance in trip, but there are no class 3 rapids. All of the rapids are 2, and riffles. Below Mehama on the river is still a good run, but only when adequate water is flowing. This section has a portage on it, and is a lot of riffles. It was great to get used to my new kayak on this section. Most of the area around the river is scenic, with some residential. It is a great river.
Packsaddle Park has a boat ramp and parking. Mill City at the bridge has a few parking spots, but also has public bathrooms right off the main road. This river is heavily used by fishermen! There is also a great place to stop for pizza at the end of the trip in Mill City, you can't miss it, the parking lot is always full and it's directly on Hwy 22.
No fees or permits are required, just check the water levels and suggested flow before going.
To get to the Santiam River, it's on Hwy 22 going East from Salem. It is west of Detroit Lake, so if you get that far, you've gone to far. It would take about 45 minutes from Salem to get to Packsaddle to put in.
The take out at Mill City is off of Hwy 22 on a road that heads in towards downtown Mill City. A LARGE bridge crosses the river and the take out is on the right side of the bridge, it's a little hike down to the river.
We have two books that we usually look in for trips: Soggy Sneakers, which is Oregon and I believe SW Washington. This book really describes the trips nicely. A new one we just got is by Falcon, and is Oregon Paddling, it has great charts for river flow.