People with a disability rating in excess of 80% can acquire free parking on presentation of their blue badge. You must however pre-book “Parking 7 E PMR” on the 24H Camions official ticketing website. Enter the circuit via the South Gate (Porte Sud) and make your way to parking area P7E. Please show your admission ticket as well as your parking permit. The blue badge must be displayed behind the windscreen throughout the parking period. No entry for camper vans. 

Yes, there are excellent vantage points located at various spots around the circuit.

Some grandstands can accomodate visitors with disabilities.
T13 SINGHER, T16 SOMMER, and T23 RACCORDEMENT all have access ramps.
T17 DURAND has a lift (for ACO members) as does T34 STANDS.