I distinctly remember that the early, pre-casting ideas for the Tuvok character were for an elderly mentor-figure type. I was very surprised when they cast someone so much younger than what the publicity had described. I remember thinking, "Well, I hope they at least put him in a grey wig."
The VGR Companion
reprints an early draft of the series bible, and it says:
The Vulcan Tactical/Security Officer is getting on in years--he's 160 (about 60 in human terms), but is as fit as people half his age.... His grandfatherly presence is cumforting to many particularly the young and headstrong B'Elanna, and his age is seen as a virtue; many of the crew turn to him for advice and counsel, and are rarely disappointed.
It also contains a different version of the passage Bill quoted:
Tuvok has lived long, but he has also lived well, tasting most of life's experiences. He married young, had four children (three of whom are Starfleet), and outlived his wife of ninety years.