You may park your car in front of the building.
From Charles de Gaulle airportCharles de Gaulle airport to Gare de Lyon (45 mn): take the RER B (express railroad) at Charles de Gaulle to Paris. Get off at "Chatelet les Halles" and then take the connection to RER A on the other side of the same platform. The next station is Gare de Lyon.
Gare de Lyon to Fontainebleau (45 mn): at Gare de Lyon take a train that stops at Fontainebleau/Avon station.
From Fontainebleau/Avon train station to Mines ParisTech (20 mn): on the same side as you get out of the train, take one of the buses to the Castle. You can buy directly the ticket on the bus (about 2 euros, it is preferable to have some change). Get off at "Saint Honoré" stop, near the Castle. The bus stop is located near the street where Mines ParisTech is located.
Mines ParisTech site in Fontainebleau: