Map of all points below a certain time of travel?

Question

My question is very simple and can be understood in one line:

Is there a way, tool, etc. using Google Maps to get an overlay of all surface which is below a certain

Answer 1

I think you are looking for the Google Distance Matrix API. It returns not routes, but duration and distance for each pair of origin and destination. It has a usage limit of 100 elements per 10 seconds.

So you can make an educated guess about the distance that matches the desired time of travel, choose six or eight equally distributed points on a circle of that radius, and query the corresponding durations. Then refine the distances according to the results and calculate intermediary points. This way you can get a (quite rough) map in a few iterations.