Yes, I think the one year Non O at Savannakhet is the favourite, multi entry. I only live about 15 minutes from O Smach Cambodia border, so a border bounce every 3 months is not a problem. Only worry really is getting from Surin to Mukdahan, driving, just in case of checkpoints, though mostly they are in the direction of Bangkok. Possibly a coach might be better.
Brian, I think you have to go through the process, 3 month extension, 1 year non O, then the child extension of stay. Not sure about that though, but surely you need a basic extension of stay to work on.?
Yes, but I have no ties in the UK, and a wife and child in Thailand. All not helped by the UK Passport service taking 16 weeks to renew a passport. Cannot get an extension of stay without one.