There are a lot of folks here that can help you with the task once you know your daily needs. Additional info needed:
1. Full time or part time cruising?
2. Living at anchor or at dock with electric?
3. Type of boat and current set up. Engine/Alternator/battery banks
4. Cruising grounds...Caribe-Mexico-Worldwide etc.
5. Available space for panels?
I too am looking at a total electrical system redo. I came across the Ample Power website. They have a technical section on electrical wiring diagrams for various systems. Here is the one you asked for: Retro-fitting Existing Electrical System. Their website has other wiring diagrams and other technical information on various boat electrical systems. I found it makes a good start when one is retro-fitting an existing system to their specific needs.
While they tout their own products, I am sure one can substitute another brand. Many cruiser bulletins like the Ample Power products and rate them as good or better than other popular brands out there. They also sell a book on electrical systems as well. "Living on 12 volts". I hope this helps.
Thanks for the references... just the sort of thing I was looking for. I have seen a few books and websites but was hoping for some suggestions of things I had not seen and/or that were better than others. Again, thank you.
The boat I am thinking about buying is a clean slate so I would be designing the system from scratch.
And Melrna, thank you for the Ample Power reference... I will be relocating to Seattle this spring and I may have to pop in and talk to the folks there. The diagram in the link you posted is just the sort of thing I was hoping for. Thanks!