How Frustrating!
Can you 'drive in' t a neighboring district?
I would certainly keep asking the Principle and then the School Board, if you win an ally they may bend the rules for you, or change them.

Of course the 1/2 day program may not actually be challenging enough, and not worth your time. Will they let you observe before you invest the energy?

Smiles,
Grinity

Coaching available, at SchoolSuccessSolutions.com