tools on the truck
This might work great for you f/t guys:
One of my friends operates an extended cab (not sure what it is in "Ford speak") F-350. Rather than carrying people in the back, he has turned the area into a mobile (though cramped) office. He's managed to wedge a laptop computer and a printer on a small, homemade desk-like thing.... nothing like end-of-job work summaries for his clients. His best tip, though, is to write down all of the tools you use on a regular (once/week) basis and carry them with you, along with spare parts. His box, convienently, fits in the back of his cab (I think it makes up part of his desk). He works full time, and I've never heard him bitching about having to head home for parts or tools, so I would think it works.
Another (random) tip. Make sure your equipment gas tanks (and your five-gals. on the truck) are full at the beginning of the day. Not much is more embarrasing than running dry on the last 1/4 acre of a big (read: high-profit) job.