If you're going to spend that kind of time creating hand-drawn maps, it's in your favor to get yourself a flatbed scanner, and not rely on low res digital camera images. I prefer hand-drawing as part of my map design toolset as well. I will admit to drawing on 8.5 x 11 sheets for elements of a map - the ship, seaweed, fish in my challenge map were done on letter size pieces, though I generally draw maps onto 18" x 24" or 24" x 36" sheets, and rarely to sizes larger than that. My commissioned map of the City of Kasai for Paizo's Jade Regent Adventure Path was drawn on a 36" x 54" sheet. Of course I use a large format scanner from my digital print/graphic design studio, which gives me an edge with large format work.