It’s hard to decide for you what places are must see for you… It depends on your interests and budget! (Food, clubs/dancing, shopping, history, art…)

A very good overall Paris travel resource can be found at http://wikitravel.org/en/Paris. It covers a lot of material, but it’s still very accessible for quick browsing.

As for transport (see http://ratp.fr), Parc Disneyland is in Zone 5, about 40 minutes from Châtelet-Les-Halles (station at the city center of Paris). A one-way ticket costs 6.3euro, but you can buy a ten pack for 50.4euro. Careful—your last train leaves Chatelet at about 0h30.

I hope you have a great trip!