If you have married a Thai and have decided to settle in North East Thailand in the area called Isaan, then you would have to make many adjustments. Firstly there are not many English speakers in Isaan so learning some Thai would be a good idea. If you are thinking of retirement in Isaan then consider obtaining a 3 month visa outside of Thailand and then extending your retirement visa in Thailand for 1 year.
This visa does not allow you to work in Thailand – not even part-time or for free. If you are considering working in Isaan then you will need a work permit to work in Thailand. Consider how you want to retire in Isaan and how you plan on passing your day.
Getting married in Isaan has been described before. One thing you might consider is healthcare and how you are planning on covering your healthcare in Thailand. There are a number of good hospitals in Isaan but they are few and far between. As an expat using the public hospitals are a big no-no and you would have to consider where the nearest private hospital is from where you are located. Take care when taking the path to live in Isaan.
There are options with regards to property in Thailand. Most expats in Isaan tend to rent property and only a few buy property as a long-term investment. Those who do buy, first rent the property before they buy to ensure that they like the area and that it suits their needs. Property and marriage in Isaan can be a problem. The Thai forums are all full of expats having problems with the wife and then being told to leave the property. Ensure that you have a usufruct or a prenuptial agreement as justice in Isaan moves very slow. Speak to a lawyer before you venture up this path as getting divorced in Isaan can present another bigger problem.