Welcome to OFF! Saw your post wondering about the santiam. Each of the two forks are independently are fairly large, the mainstem is impressive. The north fork of the santiam will provide better bank access. The flows may be a little higher and would not recomend taking a canoe until later in the year.
The rivers above detroit are more managable as far as bank access and should be loaded with stocker rainbows. The river below Detroit will have Steelhead and Spring Chinook.
The south fork has more limited bank options however has higher concentrations of Salmon and Steelhead in those areas. The hatchery below Foster Dam should have lots of steelhead available bober and jigs here work well, the water is slower, 8# test will get the job done nicely. The water above green peter (yellow bottom) has a lot of rainbows in stocker sizes and a few larger 4 and 5# fish.
What do people do with gar? I have never heard of any one eating them.