I do know that the current HS coaching staff here started the district travel program and the year that the first kids to go through the program reached Junior year of HS, they won their division and have been contenders, if not winners, every year since, so there is merit to it.
One stumbling block to watch out for in a travel program is who the coaches will be. One recent age group actually had three dads who all played college baseball on scholarship and the dads were all willing to coach, but they and their talented kids went elsewhere because there was already a head coach entrenched that they didn't see eye-to-eye with. So instead of having three coaches who really knew baseball, they had volunteer dads who were good people and generally good athletes, but none had even played HS baseball.