Nice photos and thank you for posting. It looks like a small chunk of your Eureka/Seeley Lake route was GDMBR but also a majority was other small roads mixed with the main routes. How had you worked out these particular routes?
You can take the GD route from the Canadian border area a bit north of Eureka to Whitefish, but it's days of riding. Bigfork to Seeley Lake is also on the GD, but I think it's at least two days of riding for mortals.
Much of my routing was developed on my own. Some is part of the Northern Tier route. The section between Yaak and Rexford I learned about not all that long before I headed out there in 2017. I had seen some of the roads on Google Maps and was going to go to Yaak then to Libby and then up MT 37 to Rexford. Maybe a couple of months before that trip I searched "Yaak" on CGOAB and found a report written by a guy who, with a group, had ridden between Rexford and Yaak via Porcupine Pass on the advice of a local they met in Eureka. I was pretty amazed to learn that that entire section is paved. (It's rather remote. At one point I was so far north that I got cell service again from Verizon of Canada. Had not had service in two days. Here I am ripping down the descent and the phone starts alerting me to the text message I had not received.) Because it's more direct than going through Libby it gave me an extra day to spend up there.