I travel to Paris for work often enough to visit DLP about once a year. I always stay near the office in central Paris and take the RER A train to Marne LaVallee. It takes about 30 minutes and is safe and clean (unlike the RER line from Charles DeGaulle airport which is full of pickpockets and luggage thieves).
One thing to consider if you decide to visit DLP is to fly to London and spend a few days there. Then you can take the Eurostar train right to DLP and back to London when you are done for your return flight. Airlines like
Virgin Atlantic have great fares to/from London that you won't often find to Paris.
About the park - I'd agree with those above that said DLP is the best of the Magic Kingdoms and I've been to all four many times to make this determination. The only drawback is that unlike Florida and California, DLP has a cold and/or rainy season (as does Tokyo for that matter - the first Disney park ever to have snow in January 1984). I've visited in March, June, and November. Certain DLP rides are seasonal, so a trip between September and April could allow you to do everything in a day given the lesser crowds and the closed attractions. The Haunted Mansion is very unique there, but even more so is Thunder Mountain RR which has the ride in the middle of the lake where Tom Sawyer island is in Florida. You start off on the shore side and go down under the lake to get to the island for a dark start to the ride. Space Mountain is much different at DLP as it has a Jules Verne theme and uses the magnetic start like RnR and has a loop to turn you upside down. It's undergoing a major refurbishment now and is closed until later this year I believe. DLP has some unique items like the Cheshire Cat shrubbery display that moves and grins and the Indiana Jones backwards roller coaster. The food is definitely french and even fast food can be slow. There is a Walt Disney restaurant on the left side of main street about half way down that is very good, but pricey. Given the often cold and inclement weather, Main Street has a parallel covered walkway that runs behind the stores on the left. This allows you to enter and leave the stores from the back too and is the quick way out at the end of the day if the crowds are clogging the main street.
Disney Studios is a half day park, but a fun one to visit. Just like Tokyo DL, it has a big covered main street area that is heated in cold seasons. This is the place to be to warm up or get out of the weather. A nice food court is here too. RnR's Aerosmith/stretch limo theme is lost on the French, so the pre-ride show is lame. The ride is great and you can ride it until you regret the large lunch you just ate as the lines are never long after the morning rush. The Moteurs Action show is a fun one to watch if you like Joey Chitwood type car, bike and jetski stunts.
If you stay at DLP, the Disneyland Hotel is the one to go for. The location above the park entrance is handy and cool to hang out and watch the crowds coming and going from. They have a downtown Disney type area near the train station that can be a fun break from the parks. Practice your mechanical bull riding and you'll be able to wow the locals who don't know how to stay on (hint: keep your knees up at chest level and your body compacted to lower the balance point on the saddle). As far as english speaking, the DLP attractions are mostly multi-lingual (I loved the Snow White and the Seven Dwarves sign in French) and most of the staff seems to be from Germany or eastern Europe anyhow, so I never have had an issue with having to know French to get by.
Send me a PM if I didn't cover an area you wanted to know more about.