Yes, there are other ongoing threads on tablets on the site, and one or two asking questions about scanners. A standard scanner, like the one you got, should be perfectly fine. Unless you have a really small scanner, and a very large hand-drawn map to scan into it, I would never photograph a drawing to scan it in. There is nothing better than to scan the hand-drawing directly.
Even though technically a hand-drawing is B/W, I usually scan in grayscale, then in Photoshop (or whatever software you are using to scan into) increase the contrast, lighten or darken the image as you need, otherwise you'll get artifacts or other "dirty" results which can be problematic to work with, once you've got it in software to color and finish your map.
Because I work in vector, I usually scan at 300 dpi, to have the best line results. If you go too low a scanning resolution, fine lines can become "jaggy". Of course most everyone here uses raster apps, so I guess you'd be scanning at the working resolution you use to create your map - whatever that may be.
I run a pro graphic design studio and I use an 11 x 17 flatbed to do all my graphics in.
Another thing I've learned, especially for doing hand-drawn map work, is that I hand-draw the coastlines and rivers first for example scan and place on my work map in Xara Xtreme Pro 4.0 (the proggie I use to map with) I hand-drawn the mountains, forests, swamps, city/town icons, and every other element separately. Sometimes I print out a copy of my coastal/river hand-drawning and use it to trace around while creating other elements. Thus before I'm done, I usually hava four to six different hand-drawings combined in a single map.
In other words, I don't draw everything in one sitting. I draw things in parts and add to the final map. I try to scan at the same resolution and I try to draw at the same scale as all my other hand-drawn parts, but I never hand-draw everything on a single piece a paper. Like adding map tokens onto an existing map, I hand-draw each element separately and composite the whole while working on the map. That way, if you screw up the mountains, for example, you don't have to draw the entire thing again. By doing the mountains separately, you can always redraw them "better" then composite back to the primary map.
I hope that helps...
Also we have some tablet-using masters here, like Torstan who like me does pro work for publishers. He swears by tablet use, and one day, I'll get my own and do the same. Tablet technology is getting better and better. So if you can afford, I'm sure its like the difference in not having a computer, then getting one. Once you get used to the tablet, you'll never go back to hand-drawing the old fashioned way. Still I get excellent results doing it old fashioned so make your choice and go for it. You'll eventually find what works best for YOU.