Need to do a visa run to Savannaket, not sure if i need to get a data package at 1500baht for 3 days or Dtac will work in most places along the river, does anybody have any experience?

My Thai phone didn't work there.

No idea about DTAC, but you'll have reception with AIS when you're at the Mekhong.

On the Thai side of Mekong Dtac has better coverage than AIS. I don't know if it works in Laos.

Close to the riverside and at the new location from the Thai - Cosulate I didn't had any problem the last 2 years with my Happy / DTAC

DTAC roaming works fine in Laos.