What is the best border crossing for obtaining a Thai Tourist Visa from Sukhothai: Myanmar, Cambodia, or Laos?

I need to do a border run to obtain a Thai Tourist Visa. I came in on a 30 day visa-exempt. I extended that for another 30 days which will expire next week. I could probably extend that once more but would prefer the 60 day tourist visa.

My question: where is the best border crossing of a neighboring country with a nearby consulate for doing this? Myanmar, Cambodia, or Laos? I'm in upper central, near Sukhothai. Myanmar is closest, but which country, particularly its border crossing with Thailand, is easiest for getting a Thai Tourist Visa? Canadian passport holder.

Many thanks for any advice.