Here's my experience with trying to get permits last year:
Okanogan-Wenatchee National Forest
In one sense, this NF is less restrictive compared with the Mt. Baker NF. In particular, there are no restrictions on tree type except some species can only be dug at certain times of the year. There are also no height limitations.
Links:
https://www.fs.usda.gov/detail/okawen/passes-permits/?cid=fsbdev3_053598
The challenge I faced with this NF last year is that based on my calls to multiple district offices, including the HQ office, they weren't issuing permits due to COVID. Apparently, they do studies to identify specific areas in each ranger district in which they will allow transplanting. With COVID, they didn't have the resources to do so.
Mt. Baker National Forest
This NF is more restrictive in tree choice. For conifers, they explicitly say you can transplant Douglas Fir, Red Cedar, and Western Hemlock; they also explicitly say you cannot transplant Mountain Hemlock or Yellow Cedar. Interestingly, they don't say anything about subalpine fir. They also restrict height to 2" (so, if the ranger finds you with something taller, just explain that you plant to it at an angle such that the apex will be 2" or less from the soil line or bring some rebar to bend the trunk
; j/k, I'm not suggesting you do this!). Another restriction with Mt. Baker NF is that trees must be harvested within 50 feet of a forest service road, which limits your options. However, the nice things about Mt. National Forest is there are no limitations on when you can transplant, and you can harvest up to 5 trees for free.
Links:
https://www.fs.usda.gov/detail/mbs/passes-permits/forestproducts/?cid=fseprd500021
https://www.fs.usda.gov/detail/mbs/passes-permits/forestproducts/?cid=fseprd500152
Last spring, I was actually able to find someone in Mt. Baker NF who would issue a permit. He also recommended a place with lots of forest service roads:
Stampede Pass. Depending on how busy life gets, I'm hoping to head to this area this spring.