Make certain that all of the requisite vaccinations and inoculations are current and recorded properly in your vaccinations card that is standard like your passport. While you're at it make about 6 color copies of the vaccine card and the double page of your passport and any visa's. Leave 2 at different places/people at home. Carry one copy in your wallet, one hidden in a clothing pocket that is unlikely to be laundered or stolen and finally hide one on your body. This is on the edge of paranoid so common sense is the guide. For travelers Passports are essential and a copy of your passport can be the difference between having a special issue passport and a rather immediate, possibly expensive and indignant flight home, trip over.
I am an old traveler who has boldly gone where angels fear to tread, sometimes with very serious consequences and utter blind bluff or luck with others, I have a list of friends who have thanked me for pressing some valued advice. My friend "Bill" had electronic products he needed manufactured in Asia. I was exporting manufacturing equipment made in the U.S. so we needed the same companies.
On Bill's first trip beginning in Japan, we arrived separately but met with in hours. Whenever I could, I notified the U.S. Consulate of my address in the country I'm visiting and planned departure/destination. Bill and I made the call to the consulate together. I left about five days ahead of Bill and went on to Korea. Bill caught up in Korea with an adventure he didn't want but it drove home the advice.
The night I left Japan Bill's passport went missing. After several increasingly desperate searches he concluded, correctly, his passport had been stolen. When he went to the American consulate, they began the process of arranging his flight home. He quickly presented his passport copies and it was like magic. He had a new passport the next morning and had a notice awaiting his return, confirming that the stolen passport had been confiscated.
Arrange to have a certain amount of local currency. I used to try and carry the amount of bus or taxi fare from the airport to civilization. With International travel, plans and delays can put you somewhere you weren't expecting. Singapore is the international hub for Nan Yang or the triangle of Singapore, Malaysia and Thailand. You may see Thailand, Singapore and Malaysia, they're each about an hour flight.
Don't let anyone tell you that drug transport is a no brainer in Nan Yang. It is a First World for the most part but Singapore and Malaysia, possibly Thailand have a special court for drug smuggling. People arrive, get caught, tried and punished without the main court system. All but the most important people don't even get mentioned in the news. As long as you aren't smuggling drugs, even if you lose all your extra medical documents, a bottle of 90 dilaudid in the proper bottle or such isn't going to be noticed beyond the fact it's there with other medicines.
To that end a letter describing your condition and the basic reasons for all the nebbing paraphernalia, list of drugs including ointment, nasal sprays and enzymes that we tend to forget. I've dealt with these people at least 100 times and IF they aren't dazzled by the equipment, medicines in original bottles, a letter from the doctor, on Letterhead, is gold. Many medicines don't exist everywhere and narcotics are not easy to obtain. Best to anticipate added pain from the stresses of travel. The last time I was in Bangkok, Tylenol was prescription.
Thailand is like most countries famous for tourism and cheaper to visit, lots of petty theft. I still wear a silk money belt, a super flat fanny pack that fits against the skin. Carry lots of handkerchieves, Thailand has 97% humidity and ~97°F at night! OK maybe that's an overstatement but if you forget, they're sold in convenience stores and usually the Mandarin "soap-pan" as it's pronounced, will get them. Don't advertise your possessions, keep cameras and electronic devices out of sight. Be very wary about buying non native goods. "The Lonely Planet" guides are worth as much early reading as you can afford. Read the preface and the cultural/ history and the local bargains.
I found some of the most interesting, intricate and beautiful bargains are shadow box figures. For ~$5 or less clear tanned split leather, like a drumhead, is cut out, like an ornate elephant, intricately punched in patterns and colored with transparent oil colors to represent characters in Thai TV for the masses. The jungle glows with tiny theaters made from a transparent screen and characters on sticks telling thousand year old stories or satire of local and international news.
If Thailand is your first adventure overseas, this ain't Europe. Petty theft is about the same in Paris, Rome, cities in Eastern Europe and Asia. It's not something you worry about, take precautions, anything too good to be true, is. Frankly Thailand is pretty advanced travel. It's more of an original culture, not totally Westernized. This is worth the adventure.
In most Western countries our infrastructure allows a blind person to navigate a city, solo. In the part of the world you're going to, a blind person wouldn't make it across a parking lot. I've seen 13" of rain fall hour after hour and where it goes is a huge open drain system.... You've got to be aware of your situation and surroundings.
If you're heat intolerant, plan evenings to be out. Air conditioning is the only thing that actually works, the humidity is unreal. I envy the adventure before you.
LL