Look out for where it is that you purchase your vacation package from, make sure it's from a trusted business and also make sure you make your payment with a credit card in case you need to dispute anything.
With that out of the way, let's point out the essentials about travelling around the globe on an addressless basis.
Very importantly, travel "fashionably light". Meaning that you should only take the minimalistic art of clothing with you. Some polyester pants that you can wear on a night out, but also wash and pack really quick, a pair of plain colored tanktops and a nice camera to capture it all. A ziploc bag with your travelling toothbrush and toothpaste and a couple of good books to read.
If you are planning on taking off for a good while, you'll start noticing that carrying all this stuff around will start taking a toll on you, so it's a great way to go on a Buy It There basis. And also, don't buy if you can borrow.
There are a few other items of course you must take with you, but that entirely depends on what you deem essential.
As you keep going and experiencing, make sure you find your way into cheaper deals, negotiating and offering something in return, as people love it when you can get/provide things for them, and they'll always be happy to respond in kind.
If you try to plan for and carry the necessary items for every contingency, soon you'll find yourself bringing a flashlight, umbrella, hiking boots, nice clothes to wear to a restaurant, etc. What works best is to allocate around $100 usd for every location you go to, to get the items you need, use, and dispose of later.
Also, go for the lighter weight items to carry with you. Clothes that are not heavy, can dry fast and are wrinkle resistant.
Take a nice but small camera with you. This one is an obvious one, but many people try to take the best camera out there possible, when one that's not larger than the palm of your hand with a nice 2GB memory card that takes video too, works wonders, and will definitely not regret it.