Hey Jacky, I'm on my way to aus currently, I decided to stop over in Thailand for a brief holiday first. Came here on my own, bag of nerves, nearly had a break down when I got here on the first night.
Now one week later, couldn't be happier. I've met all kinds of people, had a beer in a market with some Americans, watched the f1 with a German, and been to phi phi island with a British couple.
You may wish you weren't travelling alone at points, but trust me at other points you will be so happy it's unreal. You go by yourself you have no ties, no route planned, only obligations are to yourself. It is so easy to meet people if you want to, but equally easy to explore on your own and at your pace if you want too.
Also I went with backpack, easier to lug about in slightly rougher areas and more comfortable over a distance.