futurecatcher - first of all, wish ya the best luck during your season!!!!
No one can really help you predict IMO what the JV team would be like. You probably have a much better idea because I suspect you may know some of the players and probably the history of the school.
Much depends on how a coach runs his program in moving talent up/down. Much has to do with a strength of a particular class which could make Var or JV stronger. Much has to do with a coach and how he develops players. Is the Varsity that strong because of what he's instilled and taught? You probably know the answers to some of these and other thoughts and can figure out the answer to your own question.
Regardless of what their JV brings - you just flat out outplay them!!!!! Good luck!