I arrive to Paris on Thursday morning and will be staying at a Disney Land resort what is the most cost effective train ticket for 5 days back and forth to visit Eiffel Tower, Louvre, etc . Thank you.
For the first 4 days, the Navigo Week Pass will still be your most cost effective choice (Thursday - Sunday). For your 5th day (Monday), a Navigo Day pass would cover your travel anywhere in the Paris area. You can add this Navigo Day pass at the same time you buy the Navigo Week pass as you can set a Navigo Day Pass' "active" day up to 6 days in advance.