Thanks! The avoidance of out-and-backs was a must-have for me. It can definitely be improved though. For example, right now the algorithm tries to avoid traversing the same path twice, but it will happily use a path that is only a few metres away! So adding some buffer around that (to penalise paths that are close to one already taken, if not the same) is a future bit of work.

Your suggestion is a nice one. Here in the UK, where it's common to have trains connecting most towns and larger areas, I have thought about adding the ability to say "I want to run 20 miles, and finish at a train station that can get me home in under an hour". Assuming the user is using a car makes it more easily achievable though. Consider it on the todo list!