LOL. To me, NYC is the most “city on steroids” place I’ve ever been and is nothing like Mexico City. I’ve lived a hour north of NYC for 20 years. Hong Kong would be next.
I mentioned CDMX because for your itinerary, you most likely would fly there. The old town part of CDMX has Aztec ruins, a beautiful cathedral, a cobbled plaza, charming colonial style buildings, open air art installations, etc… There are distinct areas of Mexico City that are quite spread out. The Museo Soumaya can’t be more different from the Templo Mayor. Anyway, your itinerary is outside of CDMX so I won’t go into it more. If interested, I posted this back in 22. https://talk.collegeconfidential.com/t/mexico-city-great-for-a-shorter-break
The region you want to go to is a known tourist route that seems delightful. I find that Mexicans are friendly and helpful. The food is great.
Guatemala was lovely. It has more of an *indigenous” feel because I don’t think it’s quite as well set up for tourists as Mexico is. Antigua is very special. Lake Atitlan was beautiful and feels very authentic and not touristy, but maybe it is these days. I recall a lot of hassle from people hawking stuff to tourists, but it would not put me off going. I went there a long time ago. Having been to Tikal and blown away by it (far more impressive than the amazing sites of Teotihuacan, Chichen Itzen, Tulum, Coba, and various Belizean ruins), it still stands out as a spectacular site. We didn’t spend time in Guatemala City.
Many years ago we went to Yucatán, Belize, and Guatemala in July. It was fine, and I don’t recall being bothered by the heat. It was a long time ago though. Not that it’s hotter now, but perhaps I would be less tolerant of it. Certainly, the weather will be better in Montreal in the summer. Sometimes, when you are going somewhere and you know it’s going to be very hot or very cold, it’s fine because you are mentally prepared for it. We just went to Iceland. Crazy cold, but amazing.
I do like Montreal. We had a car, which we parked while we were there. I am sure you could do some nice countryside between Montreal and QC. I like more adventurous places though, and to me Montreal, while lovely, isn’t adventurous. It feels like a place to visit if you can’t get to Europe. No offense to anyone. I will go to Montreal again. I haven’t been to QC but have heard good things about it.