Jim, you might also want to look at a "rolling ruler"
Staedtler Rolling Ruler
No traditional but a talented tool. I carried over a lot of drafting tools to my nav kit, and can only say that everyone may have slightly different tastes in what works best for them. Three-arm gizmos from the Weems & Plath collection...old circular slide rules...some tools do racing nav problems (wind/current/course) particularly, so I'd look at the catalogs and also look at some art supply (drafting) sources for alternatives as well.
As for the mechanical pencil how precise do you plan to be? Some folks prefer a softer lead because it is blacker and easier to see, ditto a thicker lead. Probably the 0.5mm (1/2mm) is the most common mechanical pencil lead for drafting and general use, easy to get refills AND the leads are available in red and cyan (light blue) as well as a wide range of hardnesses. The harder lead makes a finer line--but if you don't need that tight a plot, sometimes a thicker line is just as good. Odds are you can try a couple out at a local drafting or art supply store. Or just buy a bag of disposable mechanical pencils (the ones with the white erasers erase best, the orange "bic" ones make a nice crisp thin line) at a back-to-school sale, a buck for a dozen. A good thing to have when you can't find "THE" mechanical pencil too.