I use the google map millage and ajust the speed for less. So if its a 70 mph zone, im only going 65. So i divide the miles by 65 or 60 and then as above add an hour for stops, depending on fuel and how far im going. Unfortunately, millage, fuel, stops and traffic all add time. The miles for both maps should be similer. The times may be different.
2012 kz spree 220 ks
2020 Silverado 2500
Equalizer ( because i have it)
Formerly a pup owner.