It's your money and if you want to do it this way you certainly can, but you might be better served by upgrading to Ultegra to save some $$$ and still have parts worth swapping to a carbon bike later on. The weight/shifting differences are minimal when the cost isn't.

Of course, you could always give the Trek 1000 to the nephew now, buy a new carbon ride fully outfitted the way you want it and justify it to the wife by telling her you're encouraging the nephew no to be sedentary.

PJ