Strava hasn't been applying all my rides to the latest challenge. I figured out a fix that works for me. NOTE: This is not for flagged rides but rides that are just not being applied to the challenge for some reason. If your ride was flagged - immediately email STRAVA SUPPORT and include the link to the ride and any other details you can think of.
The process to get Strava to re-recognize the ride, note that this just uses tools that Strava supplies to us on their website.
Go to ride that isn't being added to the challenge.
Go to the Actions pulldown. Export it somewhere you're gonna find it again. Go look there and be sure you can find it. Look again, just to be sure. If you can't find a .gpx file then stop what you are doing and just email support. I don't want you deleting your ride and then not being able to re-upload it.
Go back to the Actions menu and delete the ride (Strava won't let you have a duplicate ride, so you have to delete it)
Upload the ride by clicking the orange "Upload Activity" button at the top of the webpage.
Choose the file you downloaded in step 2.
Give it about 5 minutes so Strava will re-check your profile and load the ride into the challenge.
Bask in the glory of your hard-earned climbing.
Please note that you are actually deleting the ride, from Strava so you need to be sure of where you are downloading it to and that you can find that place. If not, you could be primed to panic...
Since I made a goal sheet for the Nunn challenge, it was easy to mod it for a climbing challenge. This is simply a Microsoft Excel / Google Doc sheet that makes it easy to plan out your rides so you know you'll complete the challenge. It has a tab for miles and one for kilometers (tabs at the bottom). I uploaded a Google document and an Excel sheet.
I also set a custom goal for the Queen's stage challenge at 14,000 feet (4,270 meters). It's just a guess on my part and you can change it to whatever you think will win that one-day event.