I can imagine you joining the line for BTS tickets in your bikini and sunnies, with your towel draped over your shoulder as you flip-flop your way to the platform to catch your train to the beach. (Sorry - just realised you're a bloke!). I am going to give Hua Hin a try this time after a couple of weeks in Bangkok. I think you'd be happier there too. It's the rainy season so you might be spending a lot of time indoors.
I paid $A500 for a 30 day trip last year and have opted for cheaper insurance with the same coverage this year for $350 (which included removing the excess). $500 Australian for a month is a lot of money. I am 70 so no insurance is not an option. The cheaper policy will almost certainly not be as easy to claim on, but the policy I had last year is now $570, and I am not prepared to pay so much again.
Travel insurance is becoming as costly as air travel. Probably a necessary evil but I can understand why people travelling for long periods are reluctant to pay the high premiums.