Ken,
How about Contax Aria with Planar 50mm f/1.4 as a primary go-around-shooting-unshaved-farmers-and-other-things lens, Distagon 28mm f/2.8 when you need wider angle, Sonnar 85mm f/2.8 when you need more or-less good lens for portraiture and Sonnar 135mm f/2.8 with Contax Mutar III 1.4 when you need long to very long telephoto? All these lenses are very light and you can possibly haul around Aria with one lens attached and another lens in the pouch or small bag all the time with you. And if you want faster lenses - just add Planar 85mm f/1.4 to it and maybe Distagon 35mm f/1.4. That is, if the budget, style and physical fitness permits.
This is more or less setup that I got and I absolutely love it for its portability. I carry two lenses, flash + bounce card, remote release cable, microfiber cloth, brush, blower, filters, extra batteries for camera and flash, one or two extra rolls of film, few more small items in one Lowepro photobag on my shoulder. Aria with one lens attached in C-6 case with strap over the neck. Pretty neat combo I think. Although I'm not sure I will want to do that when I'm 75. In this case I would probably recommend one body + one lens kind of deal. Preferably optically fast lens. Such as Distagon 35mm f/1.4 or Planar 50mm f/1.4 or maybe even Planar 85mm f/1.4 (although I wouldn't think of using it as all-around kind of lens).
Do you have any professional photo store close to you where you can rent some of these items? If so, it might be a good idea to try it first, to see if it will work for you.
Good luck!
Mike.