It's like carthook.com but we're upselling tourist activities post hotel booking.
What issues should be anticipate and how do we validate demand for this idea and what's the first non scaling thing to do?
Sounds like a middle-man business, and those keep getting squeezed harder and harder until they die. Unless you own the front-end transaction AND the back-end upsell, I don't recommend this business model.
It is far too easy for travelers to do their own booking. And unless you have some hook (like eco-friendly activities sold to eco-tourists), there's nothing to distinguish you from anything else out there.
Right now is also a TERRIBLE time to be in the hospitality/travel business. I personally wouldn't consider anything in that space until a few years from now.
If you want to be a new carthook.com in the hotelier space, unless you own the hotels and the tourism activities, you're pretty much an ad salesman. Do you want to be an ad salesman? Because that's all you'll be doing and exactly how the tourist activities businesses will see you. Another hand out for unproven ad dollars.