This is a project I am currently working on. I like to have as much info as I can before I even get on site and I find that that generally makes the site visit the most productive. I compiled this base map from some basic GPS mapped plot lines given by the client and then printed out a topographic map from Google Earth to the same scale and traced. It's also very helpful to have cleanly drawn lines rather than the highly pixelated ones that you tend to get when printing off small sections of USGS topographic maps!
