Wasn't here during the Tsunami luckily. For $150,000 US, approximately 6 million baht, you can get a hell of a nice place in the countryside and literally live like a king. I don't know if you could afford something that big, but then I don't know why anyone would want something that size either...
There are several real estate Web sites catering to Westerners which cover Chiang Mai and Chiang Rai. Easily found on Google, not necessarily up to date but representative from what I've heard from friends and acquaintances.
Problem is you have to have a Thai spouse to get freehold which you need for a single-family home, otherwise it's leasehold, meaning condoville. I suppose you could grow bananas and leechees on your balcony.
We have a 2,000 sqft house in VN on the Delta ($25K US), but have to keep it in sister 7's name because of Hanoi's deliberate incompetence in creating a national real estate registry or real estate laws that make any sense.
That happens when you steal half a country.