wallypilot,
I don't believe there is a max age for "Private/Not for hire" pilots. I worked in a company with 2 guys that flew a Global to Europe almost weekly, one guy was 74 the other was 69, and it was never an issue. - This was also for a very large management company that did charter on most of the fleet, just happened this plane and the G I was flying did not do charters only owner trips. - By the way the guy that was 74 (now almost 80) is still flying the line and managing a private Challenger 604 out of South America now... The guy will out last guys half his age, trust me!!!
This was a few years ago so maybe someone with more recent experience can shed some light.
J