I bought one of those map Rollie things before my trip last year. From china. You had to do a simple quick math calculation to figure it out but it was pretty neat. Now if I could only remember where I put it......I tend to use the graph thing on the side of the Caa paper maps. It tells you how many k between point a and point be and approx how long time wise.
I have a zumo mounted on the bike that I have not used once, too complicated and time consuming. I also have xm radio and never used that either. Too much fiddling when I could be riding.