Google Earth (or NASA WorldWind) can be useful for that. WorldWind, last I saw, could pull down all the USGS quads. We'd often drop $40 on those maps for a hiking trip, and now you can pull them down in seconds. Google tends to be better with roads and trails, although it will often be wrong about drivability in the woods. Both could display satellite images using three dimensional rendering (very helpful, and I recommend setting the relief scale to max to begin with...then reducing if you're looking at very steep terrain).

They won't replace actual scouting, and knowing the terrain, but they're fun to play with and can tell you a lot.