Got these yesterday up in my "backyard" mountains - the Mountain Loop Highway in the north central Cascades. Not known for fall color, but you can find it if you look on a sunny day.
Typical shot - splash of deciduous color among the evergreens. Helps to have backlight.
Not much color deep in the forest so along roads and rivers is your best bet.
A 70-200mm worked great to zoom into the color across the river.