This script will calculate an adjustable route between two places, plot the corresponding height and inclination profiles and give some detailed climb height information. Read on below for some background.
To use the script, enter the origin and destination locations, and select if you want to walk/bike or drive. You can adjust the calculated route by dragging the blue line, just like in Google Maps. Finally, you can move the map marker along the path to change the position of the highlight in the elevation/inclination plots in order to localize interesting height features.
See this post for more details.