Try installing the Garmin Connect App for the IPhone on the IPad. I have a 510 that I uplad via Bluetooth to my phone. You should be able to pair your Garmin with the IPad the same way. You can set up the Garmin/Strava connection so anything uploaded this way is automatically posts over to Strava.
If you need to use a cable to upload your ride files, you're stuck to a laptop or computer.