Hi Ben, My family and I are visiting Paris in April this year. We are staying just outside Disneyland Paris in Seine-et-Marne. We are hoping to do both central paris like the effiel tower and such plus disneyland paris. What kind of ticket should we get to help us get to all areas. Thanks in advance
Most likely the Navigo Decouverte week pass is best for you unless you arrive Friday (when Navigo week passes aren't usable till Monday). You'll need a 5-zone pass (default for Navigo) since you're out near Disneyland (zone 5) and will be going into Paris (zone 1).
If you arrive on Friday-Sunday you can use Navigo day pass or Ticket Mobilis day ticket (these are equivalent in coverage now), again, 5 zone, to cover you for everywhere on a daily basis.
I'm assuming you're arriving via CDG airport. If that is the case you and you are arriving Friday-Sunday, buy/use Navigo or Mobilis day passes rather than single-use RER tickets as the cost is nearly the same. 17.30€ for a single-use ticket for CDG to Paris then onto Disney/Marne la Vallee station. Ticket Mobilis 5 zone is 17.80€. Navigo day pass is also 17.80€ plus 5€ fee for the plastic card itself.