U will need TM30, landlord, condo owner should have done this for you. TM47 form filled in, passport. It is free to do

Bring both old and new passport. The immigration office should see you in the computer system when you do your fingerprints and photo, this will show them you have a visa already, this will get updated to reflect your new passport. They may ask for the old passport the first time this is done. After that you shouldn't need both when re-entering. If the visa is inside the old passport I would always travel with it.

If you plan ahead you can get a return flight to Vietnam for 4000bht. Spend the night or two. Better than giving 6500+ to sit in a bus going to the border

@Claire *****

I went to samrong imperial mall branch. But have heard others had no success. I took residency certificate, passport, Thai driving licence and apartment contract. When the women at the entrance ask what visa I was on I just said the remote working one. Was given a ticket and waited. When they looked at my passport with my DTV I told them to look at the immigration stamp, they checked with the manager I opened the account. I can speak Thai so that made it a bit easier

When getting the blue book from the landlord, copy the first page (has the address and first owner info), also get the page with who the landlord is now as it might not be the person on the first page, you will also need a copy of their Thai ID. Most will do this and it's quite common

@Claire *****

I'm in Bangkok and opened a SCB account

Global Hanoi backpackers, has free breakfast, clean

For a flight number just use Google flight search and select a date your want and use that flight number