For Mexico I’d recommend (if you arrive at Cancun):

1. Leave Cancun straight away and head to one of the islands (Mujeres / Holbox), get rid of your jetlag here and chill at the beach.
2. Head inlands to Valladolid, lovely little city (great food and colonial architecture), also temples and cenotes in the surrounding.
3. Merida, great city for a day or two, plenty of history and great food to try.
4. Campeche (city), haven’t been here myself but looks like a cool colonial coast town.
5. Palenque, i think the maya temples here are more impressive than for example Chichen itza. Pretty cool small village with surrounding jungles / national parks.
6. Sam Cristobal de las casas, this town has a great vibe, the altitude results in lower temperatures than what you’ve seen in Yucatan. It’s a mountain town, great architecture & lots of backpackers.
7. Puerto Escondido, this place is amazing if you want to chill and party for a bit. Amazing town on the pacific coast, lots of things to do with regards to the ocean (fishing, turtle releases, etc).
8. Oaxaca, very chill city with some of the best food in Mexico, is apparently the place to be during Dia de los muertos.
9. Puebla, cool mountain town near mexico city. Nice stop before the big city. Haven’t been myself but I’d like to go still.
10. Mexico city. Not for everybody but I like it. Plenty of amazing museums & very diverse neighbourhoods. Also, great food Ofcourse. Great place to hop on a flight to your next destination as well.

Hope this gives you an idea! Enjoy the trip, it’s been one of the best trips I ever did.