Will I face challenges in obtaining a 4th 60-day Thai visa in January 2019 after my previous entries?

Okay, there is some confusion by the O/P AND by posters about the difference between the limit of 30 day visa exempt entries by land and the limit of actual tourist visas you can get from thai consulates.

Right now there is a limit of TWO 30 day visa exempt entries by land in a calendar year (Jan 1 - Dec 31)

AND

There is technically NO limit to the number of tourist visas you can get from thai consulates. Each thai consulate does put a limit of how many you can get from them before you get the warning stamp which states you can't use that consulate for tourist visas anymore.

BUT

As long as you bounce around from consulate to consulate you should be able to get quite a few tourist visas before one of the consulates warning stamps you.

@La ************

, Make SURE you meet the requirements at the consulate you're applying at for the tourist visa (they are NOT all the same). Also as Mark Allan stated correctly, make sure you have the proof of funds, proof of onward travel and proof of a hotel booking when you fly into the country JUST in case you're asked. You have a history of living here on tourist visas and that puts you in the high risk category for being questioned when you fly in.

OR

As people pointed out, you could go to the thai consulate in Vientiane and get a single entry tourist visa, then cross into thailand at the Nong Khai land border and go to Udon Thani to fly where ever it is you need to in thailand. That way you cleared passport control at Nong Khai (the easiest border crossing in the country to get in and out of).

Good Luck