....... Where are the mixed signals? All i've read, from several sources,is that immigration have NOT been asking to see insurance on entering Thailand but i'll bow to you if you have knowledge to the contrary.
I thought they were asking for a bank book showing at least 200,000 baht for the 90 day non-o based on having half Thai kids at Savanakhet and Vientiane?
There are vans that run to Aranyaprathet from Prachin. You pick it up outside the big army base. Goes to kabinburi- Sakkeo- Aranyaprathet. But that border is notoriously hostile. The chief officer there is an awful woman. Don't go there!
Other than that get to Bangkok and go to Kanchanaburi. Easy border crossings there. I think the vans go from Tesco Lotus in On Nut.
.....There is no 30 day visa. You mean a visa exempt. 99% of people waltz through immigration without any need to show money, proof of address and onward ticket BUT if you have an extensive history of living in Thailand on back to back visa exemptions and tourist visas you may we'll be asked to show you have 20k or the equivalent in another currency. Having said that it seems it makes little difference these days. If you have the cash, proof of address and onward travel the IO officer can still refuse you entry because he can! Many instances of that happening now.