Visiting thailand for the 1st time ! i need some questions answered!

Some suggestions:
— Pack only what you absolutely need. Pick clothes that are light-weight, and also long sleeve and long pants. This will protect you from the sun. Consider books carefully as they're heave.
— Make sure your pack, shoes and tent are all good QUALITY.
— Things I've found valuable: hand-crank flashlight, light-weight / fast drying towel, zip-lock bags, Wet-wipes (for when you can't shower), small 1st aid kit, leather man / swiss army knife
— Pack stuff that will be 'hard to find' and these are my personal recommends (based on cost / availability): Sunscreen (can be expensive here), insect repellant (if you have particular preferences, this is available, but expensive in Cambodia), tampons (you won't find them often or cheap in Cambodia), and absolutely pack activated charcoal (this will save your life if you eat something bad!)
— You can buy bottled water almost anywhere. There are a lot of little 'shops' on the sides of the roads selling drinks, petrol, etc.

Other suggestions:
— DO NOT travel *alone* outside the cities (ie jungle, beaches, etc). I say this as a woman, and have read many reports of rape and murder. The world isn't a safe place, and only getting worse — play it safe and use your head!
— Consult a travel nurse. They'll tell you the vaccines you need. Also, they'll suggest an anti-malaria pill which I'd also recommend if you're out of the cities / in jungle.

Hope this helps! God bless!

There will always be a shop selling bottled water close by. Always.