I will be staying at Avenue de Villiers. How should I commute to Euro Disney? Same day return.
There are a number of Metro stations along Avenue de Villiers, all of them on Line 3. Take Line 3 towards Gallieni, and get off at Opera. Follow the signs for RER Line A at Auber, and take Line A to Marne-la-Vallée. You need to become familiar with the journey planner at www.ratp.fr/en
For many years now, it has been Disneyland Paris, not Euro Disney.