I have been an adventure traveler for most of my life. I have been to 130 countries. I've never been in the military but I've been evacuated from political upheavals in Iran (unmarked special forces, revolution in March,1979) and Cambodia (Royal Thai Commandos, Phenom Penh riots in January 2003). I was in a coma for 2 weeks in India from an undiagnosed tropical fever that hit hard and wiped me out. I think it was malaria. I have been robbed more times than I can remember, including passports and all money, and prevailed over numerous other robbery attempts. I was once drugged at a resort pool in Mexico in the afternoon. It knocked me out until the next day. I was in jail in Mexico long enough for the people who arrested us to feel convinced they had all our money (myself and two guests from Norway who I was hosting.) At the airport near Cabo, the military guy in charge threatened to confiscate my Cessna 172 in no uncertain terms if I didn't pay him a substantial "parking fee."
Off the top of my head, here are some things that come to mind for the part of Yucatan you will be exploring:
Mosquito & bug spray, good quality condoms if you're single and available, money spread around in different hiding places ....
Emergency contact information for the nearest US consulate or other people and organizations in Yucatan who can help you in an emergency.
It's a good idea to scan or photograph all your documents, credit cards, credit card cancellation phone number, ID, personal information, copies of prescriptions or medications, eyeglass prescription, etc., and store it online so it can be retrieved if you lose it during your travels. Even in an email to yourself will work. Make a second set of copies to carry with you in a different location from the originals.
It's a good idea now to use RFID wallets & neck pouches and faraday cages to prevent remote skimming of your passport and credit card information. Keep your money in your front pocket, not back pocket. Keep a small amount of money in a junk decoy wallet that can be given up in a confrontation. Keep some easy-access bribe money in another pocket, separated from your main stash.
Here's a cheap and inconspicuous faraday cage that I use for my iphone and other things I want to block:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
If you are carrying a tablet, this one is bigger:
https://www.amazon.com/dp/B077GTPZYD...v_ov_lig_dp_it
CLOTHES AND TRAVEL GEAR for the tropics - things that keep you cool, covered from sun and mosquitos, things that rinse and dry instantly, a hat to protect your eyes, good quality UV block.
If you wear eyeglasses, take an old pair as backup.
Dress to look as humble and inconspicuous as possible.
A-1 Travel often has a rack of travel clothes on sale that are good for where you are going.
PacSafe
www.pacsafe.com is one of my favorite sources for durable travel gear.
HEALTH & TRAVEL VACCINATIONS:
Basic: measles-mumps-rubella (MMR) vaccine, diphtheria-tetanus-pertussis vaccine, varicella (chickenpox) vaccine, polio vaccine, and your yearly flu shot.
For 3rd world countries, tropical areas, and where you are going: hepatitis A, typhoid, hepatitis B, malaria. Start taking your malaria pills about a week before you leave, and continue them for a week after you return.
Read about about food- and water-borne diseases. Read about zika, dengue fever and chikungunya virus. There are no vaccines for these, but you can take measures to avoid mosquitoes.
Lonely Planet Health planning for Yucatan Peninsula:
https://www.lonelyplanet.com/mexico/...d097354/361679
READ RECENT TRAVEL WARNINGS and narco news:
https://travel.state.gov/content/tra...-advisory.html
http://www.borderlandbeat.com/
OTHER READING:
https://www.lonelyplanet.com/mexico/yucatan-peninsula
https://www.lonelyplanet.com/belize
10-DAY WEATHER FORECAST:
https://weather.com/weather/tenday/l...+MXQR0138:1:MX
Take lots of pictures to share with us when you come back.
Have fun! Travel safe!