double entry visa works like this: its a visa where you get 60+30 days. When your nearing your 60th day you can go to emigration and extend it with another 30 days. When that last 30 days are almost over then you need to get your ass out of the country to activate or "claim" your second half of your double entry visa. Which is another 60+30 days. After that you can go to Laos to try and get another dbl entry visa or do a visa run where ever you want to. Keep in mind that if your issued a dbl entry visa you will have a "enter before date" on that visa which means you should claim your second half of your visa before, not on, but before that date. If you do it on that date it will not be activated and you loose your 90 days. If your in the south of thailand then Ranong/Myanmar would be ideal to do your 1st border hop, it cost me 1500 in total. Ask for Esso at the docks, young guy crooked teeth. He will sort you quickly. If your in the north, then laos i presume will be your way to go. Havent been north yet so no real info there. Good luck