Hi OP. Did a solo to Thailand around 6 or 7 years ago. Some great advice above. The hotel I stayed at in Pattaya, (Can't remember the the name - sorry I'm old)!! - was very visitor friendly. Some don't like you taking girls back to your room. But there's loads of info online. Agree about the room safe totally - it's vital. I gave myself a cash limit every night and took out only that witch I needed. My phone stayed in the safe for 90% of the holiday. Stunning country, stunning girls who are are just wonderful to be with.
My best memory was taking 3 girls back to the hotel, having all the fun I wanted, then recovering for round 2 while I watched them play with eachother. Best all-nighter of my life for around £60 sterling.
If you do your research, you will have the time of your life. But you definitely need longer. I went for 21 days, and it wasn't long enough. I didn't just go for the sex, I really wanted to see the country as I'm a history freak, and love laying on the beach too. It's a fascinating, beautiful place and 90% of the people you meet will be amazing.
Don't get me wrong - most of my time there involved having fun, with my dick in some lovely welcoming orifice!! But it's a fantastic country. When I got back to the UK, I took a week off work sick just to recover. Told them I had some horrible infected insect bite!! Lol.
Oh yeah, just a tip. The chaimbermaids at the hotels get paid shit. My first morning there, I was just dressed after a shower when she tapped on my door. I said come in, and got chatting to her while she bustled around. I couldn't believe how little they are paid to look after a whole floor, and most of them are living in shitholes and sending their wages to their families. Her name was Fei. I told her to look under my pillow every morning and there would be a little something for her. They aren't supposed to take tips, but she was such a sweet girl, and I insisted. Every day I left the cash there, and every day my room was totally spotless. It was only like £2 to me, but it meant she could buy toiletries and food. The morning I left, I got the best hug I've ever had from a really sweet girl.
Treat the hotel staff with respect and you'll have the best time. Love Thailand and really need to go back.