welshTerrier2

I'm the route planner for my bike club and I doubt you'll find software that lets you specify a distance between point A and point B.

There are lots of other parameters software developers could add to mapping software. For example, you could request a certain amount of elevation gain to make a ride hillier or flatter. Or, you could ask to minimize solar glare on your route depending on the time of day (and time of year) you're riding. Or, you could ask for the most scenic route, for example, the most time riding past water views. Or, you could ask for roads with bike lanes. Or, you could ask for the lightest car traffic or the fewest intersections. There is an almost endless array of possibilities that someone might find useful.

And, after all that, you could get really crazy by allowing for multiple factors and allowing the user to "weight" them. For example, you could ask for a very hilly route with good scenery that's 10.2 miles long but make the hills the most important, the distance the second most important and the scenery the least important. The route provided would incorporate your weighting factors.

Perhaps someday, human knowledge and experience in route planning will be completely replaced by software. For now, I use RideWithGPS. Just set your starting and ending points and then "play" with the interim route until you come close to the distance you're seeking.