The Conseil Général of the Hautes-Pyrénées has a useful Tour de France  info website. (in French).

It includes a nifty clickable map that tells you at what time the Caravan and riders will make it to various sections of the route during stages 12 and 13.

Road closures:
Lowland and valley road closures start 2 hours before the caravan until 30 minutes after the race passes. Mountain area closures will be dependent on the demand for parking.