Backstory: Planning vacations and trips are time consuming and can be difficult to plan. Often times I want to see major attractions but I'm also trying to find hidden gems. I spend a lot of time and ask friends "what should I see?" Having a preplanned tripped that appealed to my tastes and preferences would be useful.
The Idea: A preplanned travel schedule based on your past experiences and likes.
Deep Dive: You could start by asking users to fill out a survey and based off these answers you could plan out a set itinerary manually. You would then send a survey rating their experience. From this initial seed data, you could start building an AI platform to predict and plan an itinerary based off overall past experience.
Additionally you could get facebook likes and any other personal data to help identify correlations to the "perfect" travel plan.
Validation: Everyone loves to travel and adding value to that experience is a huge win.
Monetization: You could charge a per travel location fee. If the first experience went great, it would entice users to purchase additional spots. As you find more popular spots you could start charging more. You could also charge an additional fee to book everything like a full travel agent.