What boat shall I buy?
The concept of creating a crewed charter opportunity catering to younger sailors is an interesting one. I would suspect that you would want a higher performance boat to keep a younger sailor''s interest and a lot of toys, windsurfers, kayaks, diving gear, etc.
That suggests a larger boat, probably something around 50 feet and a comparatively light boat. It would not suggest a low performance boat like a steel ketch. It would suggest something that is reasonably low maintenance so that you can keep charter rates lower (young people usually have less money to spend). Studies by respectible sources consistently suggest that steel tends to be one of the highest maintenance materials out there.
I would think that finding an older race boat that has been adapted to cruising would be one way to go as there tends to be a lot of volume on board and it would offer a lot of performance. Big cats are another excellent way to go in terms of speed and volume(although big cats, even at speed, really do not feel very exciting).