Tried seeing if googlemaps offered a range function which measured how far you could get once you input average speed, hours of riding, etc. Nothing found but then I didn't spend a lot of time searching either.
I tried googling the phrase "map radius" or some such and stumbled upon this site: Free Map Tools
They had a map utility that lets you: Discover how far you can travel on land from a fixed point. Specify the start point, then input either how far you can go or your mode of transport with time available. This tool will then show you the range of locations that you can reach in that time on an isochrone map.
So as an example, I put in my home zipcode, average speed of 45 mph and eight hours of traveling by driving and got this result:
source: Free Map Tools
The map shows me how far I can go, by driving (or in my case, riding), within stated parameters. Of course, it can't account for you going faster in some spots or taking pictures in others but you get the idea. In the above example, a day's worth of riding would get me to Green River, UT on the westernmost edge of the shaded area on the map.
I'm thinking one could use this tool to estimate overnight stops, estimate days of travel required to reach some final destination and so on.
For instance, following the model above, I used Green River, UT as my jumping off point for day two of travel and got this:
Starting from Green River, UT...could reach Elko, NV
Day Three of travel, starting from Elko, NV would put me within
striking range of Sacramento, CA
I mentioned mapping toys in the title of this post. Check out the Map Tunneling Tool, it allows you to select a point on the map on the left screen, and the corresponding point on the Earth if you could tunnel straight down from the selected point is displayed! Cool beans. So now, you can prove that one can't really dig his way to China, at least not if you're in the USA! :)
Digging straight down from center of USA would put you
in the Indian Ocean!
Finally, an area calculator using maps. In the example below, I found a satellite view of the local elementary school, designated the building with the tool and it tells you how much area it covers. Not 100% accurate, but still, a neat tool.
Oh the things one finds on the Internet.