1. Track your activities using a Windows Phone app, like Runtastic.
2. Connect your Runtastic account to Strava so your activities are automatically ported over there. According to Strava, Runtastic is one of several compatible programs, and they also happen to have a Windows Phone app: https://strava.zendesk.com/entries/20950143-Uploading-to-Strava-Website#fitnesssite
3. Connect your Strava to Singletracks using Tracker. This will automatically import your Strava MTB rides into Singletracks, and will check you in. http://help.singletracks.com/support/solutions/articles/3000000789-how-to-connect-strava-to-your-singletracks-account