My 2 cents... All of the part 91 charter pilots I know (admittedly a few) got there through instructing. Not airlines. It seems if you really want to land a cushy charter gig or even just flying some rich guy around in his own airplane, it helps to instruct for a while (preferably at a busy/reputable school). You tend to meet a lot of people and make good connections. A lot of guys get wrapped up in the life once they reach the airlines. I plan on instructing for about a year or two until I'm fully done with all the school I want and if something hasn't come along by then... I'll consider applying at regionals.