Phil, yes when I tour, always make routes for every day, sometimes for a weekend or even a day out.
I use a Garmin XT & put all my routes on it on a day to day basis.
I do that via Garmin Drive on my phone, I leave the routes in a folder on my phone & also upload them to Google Drive, that way if I lose them on the XT, I've still got them on my phone & if that should fail Google Drive.
Belt & braces & all that, but it takes seconds to do it all & time won't be wasted on our tours if anything should go wrong in that area.
Obviously if I need to use Google drive data (or WiFi) will be used but from the folder on my phone the .gpx is transferred via Bluetooth to the XT.