Getting to DLP before the RER begins operating

[jeanigor]

Some friends and I are participating in the DLP half marathon weekend. When we booked, we booked an offsite hotel (Relais Spa Val d'Europe).
There is some concern that we will need to be at the starting line of the races (not entirely sure where that will be exactly yet...but somewhere on DLPR property) well before the starting time of 700.
If the RER is indeed not operational when we need to go, is the best option to rent a car for the weekend and drive ourselves? Is there an alternative option?
I don't see anything about a shuttle service from the hotel, and I wouldn't expect it to start operating that early if it was offered.

 

[Torchy]

You can walk to DLP in 15-20 mins from Val d'Europe, the Relais is on the outskirts of the complex and closer to the parks than our hotel. We walked every day.