Spot on, jerseydad. That is exactly what keewartson's team does.
There is a dollar amount that is expected to be raised each year (per player, JV and V), and another amount the family is expected to pay "for the trip" (V). If more than the expected amount is funraised by the player, the less the family has to pay "for the trip".
Over the last 4 years, whether 250 miles traveled for 3 nights or 2500 miles for 7 nights, the amount needed to fund raise/pay was the same, which may have been due to generous donors to the program some years.
And since I have not been asked for money until long after the trip, my educated guess is that the current year's trip is paid for from the monies collected the year before.
The players travel as a team by chartered bus/other and parents going on the trip is purely optional.