Manual route planning for walkers/runners/cyclers.

My idea was that there are lots of fitness style apps that track where you've gone, how fast and so on, but I haven't seen anything that lets you plan your route out beforehand, see how long it'll be and then estimate how long it will take. I was thinking drawing a simple overlay on a map interface. I recently got back into walking/running and wanted to slowly ramp up what I did, but wanted a route I could get all the way through (not run until I can't, then have to still get back) so wanted to plan ahead, and also allow for cuts through parks, bush trails and so on.