Sometimes, average elevation gain does not tell the story. At least not the important part.
Here's an example of a route that feels much harder than the average would indicate. It's 51 miles, but it has only about 63 feet per mile.
It has several short but steep climbs that beat mightily on my legs. The final climb has an extended section at 15%, at which point I find myself uttering curse words to nobody in particular.
I'm resolved to repeat this route until it becomes easy (or at least easier).
Steep roads of Los Gatos 51