That's why I used Google Maps in the few instances where I needed to re-route over a long distance. Ahead of the TCR I cached enough coverage for the entire race, so I always had quick navigation with or without a connection.
I didn't have to do any really big re-routes and had offline maps in the form of Google and OSMAnd. In the end I mostly used 1000 with RWGPS coming into plan after 'swimming' across Montenegro.
I had one re-route in Italy, but that was on major roads and was easy enough anyway. I only ended up using G Maps if I was routing to a hotel I'd just booked, but it was always there as a backup option.
That's why I used Google Maps in the few instances where I needed to re-route over a long distance. Ahead of the TCR I cached enough coverage for the entire race, so I always had quick navigation with or without a connection.