Our rule of thumb is 3 hours from arrival at MCO to walking into a park, DTD or a different resort from the one we're staying at and allowing an additional hour for a dining reservation so around 8:30. At all the TS restaurants booked through Disney there is a $10 per person no show penalty you have to be willing to pay if you miss your dinner reservation because of travel delays. However, you can book restaurants in DTD directly and not have to worry about the no show penalty.