We rely on Disney transportation because we don't rent a car, and I think the recommended travel time is exaggerated. I just don't worry so much about it. I have never been so late to a reservation that I wasn't greeted politely and happily seated. Am I often there 15 minute beforehand? Absolutely not. I strive to arrive at the time I booked. Usually if I leave about 45 minutes to travel, I make it easily. If I'm late, I'm not too concerned. I refuse to stress so much about a dinner reservation on vacation.