Being new to Chiang Mai please can you advise me on the nearest, easyist place to apply for 60/90 day tourist visa to stay in Thailand

Vientiane would be the normal choice for a tourist visa.

Vientiane Laos would be closest and least expensive by crossing the bridge in Nong Kai. You can get a 2 entry tourist visa with a validity of 90 days which using 30 extensions from immigration gives you almost 6 months in the country.

Nok Air fly's to Udon Thani from Chiang Mai and offers bus service to complete the trip to the bridge.

Edited October 10, 201213 yr by ubonjoe

Thanks ubonjoe, but is this just the border? is so can I use The border at Burma (Chiang RaiI)?

You have to visit a Consulate to obtain a visa - not a border crossing.