Found this at Stickman Weekly last week FYI.

I have made many visa runs from Pattaya to the Cambo. border at Hat Lek, but have never used a visa run service for the simple reasons that they leave at the ungodly hour of 7 AM or so (in order to get you back the same day) and cram you into a claustrophobic's nightmare of a mini-bus. 

Here's how I do it: I take a well mannered, semi intelligent bar girl for company, wake up whenever I feel like it (generally around noon), have a leisurely breakfast, take a songtaew or two out to Sukhumvit Highway, and wait for ANY bus heading south/east. 

My destination is Trat, but I don't care if I have to change busses along the way at Rayong or Chanthaburi or wherever.  The Thai bus system is simple.  Upon arrival in Trat, I check into the Trat Hotel, which has decent, simple rooms for pretty cheap (I think around 400 baht last time); have dinner at the night market right outside the hotel, buy beer at 7-11 across the street and return to my room to drink myself to sleep. 

I wake up the next day, (again), WHENEVER I FEEL LIKE IT, eat a leisurely breakfast, check out and go to the minibuses around the corner and across from the bus station for the 100 baht / person drive to the border.  Minibuses leave approximately hourly. 

At the border, it's the usual border run red tape: a few forms and some money to be paid (far less than you'd have to pay a visa run service), then I take another mini-bus back to Trat, have lunch in town, and take a bus back to Pattaya.  Simple!  Comfortable!  And cheap!

Source: stickmanbangkok.com

i did that same visa run two years ago except from Bangkok about 5 times. i recommend taking 2 valiums each way which allows the trip to take only 15 minutes.

go to the minibuses around the corner and across from the bus station for the 100 baht / person drive to the border

for 300 baht ROUND TRIP there are hungry drivers waiting when the buses arrive in trat. they will pass the crammed minibuses on the way to the border and get you there in less time.