Occasionally, I am looking for a hotel not too far from some location, such as a conference center. Not too far is then at first within walking distance, say up to 20 minutes walking. Can I highlight a region on Google Maps around that location, indication the (more or less circular) area from where I can walk to that location within 20 minutes?
The type of map you are looking for is called a "isochronic map", and a quick Google then gives back gems like ones mentioned here : http://urbandemographics.blogspot.com/2011/11/travel-time-maps.html
I don't think Google Maps does it natively yet, but there are a couple of third-party apps that do. Here's one that works: http://cartoo.dyndns.org/ (Another possibility is http://www.freemaptools.com/how-far-can-i-travel.htm, but it doesn't seem to be working right now).