I've been frustrated with the driving instructions of quite a few climbing topos. No matter how good the verbal instructions, you just can't beat the map. However, if the map is rough, it can be even more frustrating than the verbal description.
If you have schematic map and not all of the roads are marked, figuring out which ones are marked is nearly impossible unless the map clearly identifies which roads are marked using either (or both) the road name and/or number.
Don't even consider drawing any map as a raster image. Vector is the only way to go for scalability and editability. If you need it as a raster image, fine, export it into a raster format of your choice, but don't ever consider drawing the map as a raster image.
My take on the best way of drawing maps is to draw them in scale. By far the easiest way of doing this is to use real geographic map as a guideline, then draw a vector map over it. Very easy to create scale-accurate maps this way. Using layers available in all remotely good illustration apps, it's even possible to easily create different versions of the same map within same image. This is very handy e.g. for different language versions and for different scale versions. Granted, vectors scale nicely but if you downsize a large map to very small size, there's often so much detail, that you just can't read the map any more. Not to mention that text needs to be certain size in order to be readable.
Furthermore, in the current era of GPS navigators the GPS coordinates are valuable help as well.
To ease the pain of drawing multiple maps, use symbol sets for common symbols.