It's great that you managed to get cron working the way you wanted. However, I'm curious, why not just put your Vim settings on Dropbox or something like BitTorrentSync - then alias your local settings/configs on each machine to the corresponding file/folder in your Dropbox?
I use this method for all settings and configs that I wish to share across multiple machines. Personally I find it more manageable than any other solution, and certainly less convoluted than "multiple rounds of ssh duncan@some-server... git pull origin master".