You can use a VGPS to generate a list:
Go to the "Map of challenge caches" page (
https://project-gc.com/Tools/Challenges?map )
Under "Show", select "has checker"
Under "Exclude", select "Archived" and "Not fulfilled" (and "Disabled" if you don't want those either)
Select whatever location and D/T limitations you like and click "Create map"
From the VGPS controls on the left, choose the selection tool. Draw a path around the caches you want. Then choose the add to VGPS option.
Go to the VGPS page and select Export->Build GPX
