I live and work in SE Asia for 10 months of the year and have done for many years. Patong is Benidorm but without the class oO. Rip-offs abound and increasingly has spread to the rest of the island. Thailand, the real Thailand, has to be one of the easiest places in the world to travel around, do it yourself, just book a flight.
June isnt exactly the wet season, its a great time to go. Yes there may be rain but its usually short bursts late or early and then clears up and is a welcome relief.
pat.... all depends what you want really. Bangkok has everything. Great nightlife, great markets, great food, historical sites (and the sleaze side of life if thats what you want) and is very very cheap even with the pound being so poor. I have my favourites. but you have to be more specific to what you'd like. I've been many times to thailand but I head to other places like Koh Sok National Park Railay Beach Ko phayam Samilian Islands Pracup Kiri Kan and many more. but if you decide only to do bkk for 5 nights. I would probably stay near the centre....between sukhumvit soi 1 to 24...would be my advice for accomodation.
put it this way, go ANYWHERE but Patong, unless you are interested in sex tourism
dont book that trip, normal boat trip will cost £20pp. as for phuket, patong is the busy place, but if u are a couple, or elder, then go to the other beaches. I've been twice..