Hiflier, your son should never have had to make a choice between travel ball or high school ball. It reflects poorly upon the high school coach who put him to that choice.
In my current situation, I have been able to come to an agreement with my son's high school coach that seems to be working well: I call him every Sunday night to coordinate the next weeks schedule, allowing the needs of the travel ball team to prevail (i.e. for pitching availability, etc.) where there would otherwise be a conflict.
This is really a win-win situation for the coach and for my son. My son gets more training/practice sessions throughout the week than he would with his travel team alone, but still gets to play against the MUCH tougher competition that the travel ball allows. The coach still gets the input into player development, progress and evaluation that he wants, and also gets a reasonable amount of availability for the allowed high school games.
This being the first year of this new rule, I think it is important to share experiences. I find it reasonable that the summer ball policy may become a factor in one's selection of high schools, where a choice exists.