Check you have repatriating medical insurance. This is mandatory and needs to be in place two months prior to the tour start date. Repatriating insurance for the specific risk group of ‘touring cyclist’ is available through Annualtravelinsurance.com and many other insurers.
Check you have the right map for your Garmin or other GPS and that you understand how to use it.
Check you have six months left on your passport.
Volunteer to help organise the tour. There’s plenty of work for the organisers to share!
Read the suggested packing list, and try to borrow or buy the spare kit you might need.
Tell those bastards at work you’re leaving, never to return!