solardev
I've used Wanderlog to plan some trips recently, and they have an "Auto-fill day" feature there. I don't know if I'd trust it because it doesn't really know my interests, budget, etc.

I was also recently in a beta for Google Maps on Android that could generate itineraries, but it was mostly trash and I stopped using it. Not sure if they ever made that live.

al_borland
ChatGPT is decent at giving things to do in various cities. I wouldn't follow any of it blindly, though. I'd view it as just another way to get some options, and then prune it down to what I actually find interesting and would enjoy.

As far as commutes go, I generally find the big mapping solutions to be pretty good. I usually use Google Maps for points of interest, but like Apple Maps for subways/trains, in cities it supports. I will sometimes pair this with some other searches and forums, to see if there are special notes about commuting from the airport to the city center, or things like that. Getting some of that inside knowledge of how a city works will probably be the most difficult thing, unless the AI can surface it from existing information that's out there... but I don't know how that will work over time as new options are releases, and people aren't talking about it anymore, because AI is "magic" and the forums shutdown. There is also a question of the traveler's preferences. I don't always want the most efficient route. I often want to balance efficiency with price, comfort, and ease.

There are some AI travel agents popping up, but I can't speak to how good any of them are. That's ultimately seems like what you're looking for. Or if you don't mind spending money, getting an actual travel agent, they will do all this stuff for you. I'm sure big sites like Trip Advisor, Booking, and others are all working on this kind of thing as well.

The Rabbit said it was going to do all this... "plan me a weekend in LA... book it." Of course, we've now seen that is all a scam, and I don't know anyone who would want that, without tweaking and tuning things before booking.

Sometime like this also sounds rather inflexible, booking everything up front. I will never forget, I was at a tiny bar in Tokyo when a couple from the UK sat down next to me. They had just arrived, maybe 12 hours before. The husband pulled out their itinerary to show me and it was massive. Probably 20+ pages. It looked like something AI would have spit out, if that was a thing at the time. They told me they were already 2 pages behind. There was no slack built into their schedule, hopefully they didn't have anything non-refundable booked. I was stressed out just talking to them, knowing every minute of their days were regimented out, and a simple drink at a bar was throwing a wrench in everything.

What I would rather have is an AI companion that would be with me during the trip. Let me figure out options up front, then based on weather, my own energy levels, importance, booking difficulty, etc... let me work with the AI in real-time during the trip to figure out what's next to hit the things I want to hit during my time there. If there is a museum on the list, that doesn't need to be scheduled at a certain time, it can be more of a.... "it looks like rain today, might I suggest checking off some of your indoor actives, like museum X, restaurant Y, and pub Z. Leave at 9 to avoid the rain if walking. If you'll be leaving after 10, I can call an Uber." Or, "you walked 12 miles yesterday, today might be a good day for a bus tour around town, with an evening at the theater, I see tickets are available for the 7:30 show. Should I book them?" Maybe have a tentative week, lock in some tent pole attractions that typically sell out if not booked in advance, and let the rest be flexible and adapt based on how things go. Another thing I'd like is for it to be location aware. I'm in spot X, "thing Y on your list is right around the corner, do you want to check it out while you're here?" Or, "it wasn't on your list, but there is a small chapel that is a popular tourist spot, it is one block up and on your way to your next planned location. Would you like some more information?"