|Washington Peak by Wsiegmund CC BY|
In comparison, looking at the GDMBR, north of Breckenridge and including the Canada section, I could only find one section with that kind of gain/loss (Galton Pass) and if you take the route in the southerly direction AC recommends, it is a downhill.
My cycling partner looked at many blog posts of people who did it in its first year of available maps and came to the conclusion that you can probably only do 20 miles a day, at least on the singletrack, and not much more on the main route.
The main route is a 517.6 mile loop out from Idaho City and includes a singletrack option from Boise, allowing easy airline access. There is a shortcut across the middle back east, in case you need to bail. The singletrack options, by their very nature, are long and remote.