The calculated distance (air line) between Rambouillet and Marne La Vallée is approximately 39 miles respectively 63 kilometers.
By car or train, the actual journey to Marne La Vallée is certainly longer, as only the direct route (as the crow flies) between Rambouillet and Marne La Vallée has been calculated here.
Air line (approximately)
63 kilometers
34 nautical miles