My family and I go on a big roadtrip across the country every other summer with the goal of staying overnight in every state by the time the oldest kid reaches 18 years old. To make the trip a bit more fun during the hours of driving, my wife had the idea of making a really large map that we could pin to the ceiling of our car and mark as we made our way across the country.
Google Maps is a natural choice, but it doesn't make it trivially easy to create tiled images like this, so I invented my own system.
First, create your ideal route via Google Maps' existing route creation tool, continuing to add destinations and including your trip back home.
Next, share the map via the menu, and click the "Embed a map" link. The resulting <iframe> tag is a link to the map including your route. Choose a custom size from the dropdown and pick some large numbers, like 7000 x 3000.
Now, make a new HTML file that contains this embedding alone. No need to worry about the proper <html> tags here; the browser will still render the map. Open the new file in Chrome. You should see your map, but at a very large size.
Next, install a screenshot extension that can take a picture of the whole page, not just the currently visible content. I use Full Page Screen Capture, which does the trick. When it finishes, choose to download the resulting file as a PNG
Now, convert the large PNG into a multi-page PDF that can actually be printed on a real printer. To do this, I use PosteRazor, which is designed for exactly this purpose. I load the image and split it into 8.5" x 11" or 11" x 17" paper, depending on if I can print this at work. I typically print on cardstock.
After printing, trim off the unprinted area from two adjacent edges of each piece of paper with some scissors or a paper cutter. Then, line up the pages and tape them together, creating the massive map!