You can also buy a GPS program that allows planning a trip on your laptop, then plug in the USB port GPS receiver and use the laptop as your 15" screen GPS unit!
DeLorme has TOPO program 10.0 (last time I checked) and higher versions. Once you pick a start and stop, put in any side trips, then you can click something to calculate the hills, it will give the steepest section, and you can look at a profile of the grades!
Planning a alternate route without some of the steep grades is also possible.
Fred.