The other potential gottcha with the Garmin is that it displays the arrival time in the time zone you will be in when you arrive. I know that got exciting to me one evening out in the middle of F"n nowhere when I ended up with 50 miles to the closest gas station and about 40 miles of fuel. Fortunately at 40mph the mileage was enough that the Honda Shadow made it into town. Put 3.9 gallons into a 3.5 gallon tank.
One of these days I may actually read the instruction manual for that gizmo, but I doubt that's in there.
'07 Norge - the fast red one
'03 Honda Shadow 750 - Rocky
'99 Honda Helix - Little Zippy
'76 Honda CJ360T