For baseball the HS varsity teams travel to a tournament. Not mandatory, but last year everyone from my son's team went. A couple of the best JV players may be invited to join. In our experience, JV was off for spring break.
If your kid is on JV and you're wondering if you should take a vacation, the answer is yes! Once they are on varsity, there go your spring break plans unless you want to travel to NC, SC, or FL to watch a bunch of baseball games.