Hello,
My son and I just did a Paris trip this March. In total, we were gone 10 days. This is what we did, if it helps.
Day 1 - 7: Stayed at an Airbnb in Noisy le Grand. It was right on the RER line. It was 15 min to central Paris, and 15 min the other direction to Disneyland. We mostly did Paris sights during this time except for a day trip for D-Day tour. We took an early train out of Paris to Bayeux, toured a museum then joined a 1/2 tour by
Gold Beach Company. It was fabulous! Our guide was incredible and very knowledgeable. It was more than enough time for us. Afterwards, we ate dinner in Bayeux then took the train back into Paris. The train trip was 2 hours each way on Euro Star. It was very reasonable, $173 round trip for 2.
Day 8-10: Stayed at the Radisson Blu in Marne la Vallee. Room for 3 nights, with breakfast included, was 302 euro. The hotel had a complementary shuttle that ONLY went to Disney and their hotel. It didn't stop at other hotels. The breakfast buffet was excellent. Lots of choices. The staff was very friendly. We decided to stay off property because it was so much less expensive for us.
How we saved some money:
Paris Disneyland Annual Passes: We realized that we could save a good portion of money by purchasing their most limited Annual Pass, Discovery Pass, for $179 euro each vs $255 euro for a 3-day ticket. Now, keep in mind, the Discovery pass is the most limited pass. It only has 150 valid days. It is mostly valid Mondays - Thursdays. HERE'S THE CATCH. To keep tourists from purchasing this pass it is only good on day 1 then not again until day 4. So, if you go on a Saturday (which we did) and purchase/activate the pass then you
cannot use it again until Tuesday. It worked just fine for us because we knew ahead of time and built it into our schedule. You can purchase ANY pass, ANY day regardless of the type, even if it is a blackout day for that pass. I hope that makes sense.
Train Tickets: Again, it pays to do your research. There is a little known unlimited weekly pass you can purchase for 22.80 Euro per person, per week. It is the
Paris Navigo Decourverte Pass. You can purchase this pass at the airport by going up to the Metro ticket window (they are not available through the machines). You need to bring a 3 cm tall by 2.5 cm wide photo of yourself for the pass (we printed ours at home on regular paper - they didn't care). The pass will have double-stick tape on it to secure your photo. There are photo booths in the airport, but usually there's a line. They are going to charge you 5 euro initially for the plastic pass on top of the 22.80 weekly fee. The pass is good from Monday 00:00 am through Sunday 23:59 pm. This pass saved us a lot of money, time and stress. The pass is for unlimited use on trains/metro/buses. It more than paid for itself just by using it to go from CDG airport into Paris.
Paris Tips: Bring your own wash cloth/bath scrubber from home. We didn't realize that hotels don't provide them. They are considered a personal item and most people travel with their own. Who knew?
I hope that helps. Enjoy planning your trip - it's part of the fun!