Thanks for writing, Terence!
The park-hopper option has a flat fee regardless of the number of days you purchase and/or the number of days remaining on your ticket. The fee as of April 2010 is approximately $55 (with tax) to add the park-hopper option to your Magic Your Way ticket. If you want to visit more than one park on any day you use your ticket, you will need to add the park-hopper option.
Please also note that the maximum number of days you can purchase on a single Magic Your Way ticket is 10, and they expire 14 days from the day you first use your ticket, unless you add on the no-expiration option.
Hope that helps!
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on this page. (Note: you can submit questions to other panelists in the same way, via each panelist's "Meet the Moms" personal bio page)