Will my return ticket cause problems at the airport since it exceeds my tourist visa validity?

You wont get an extension on the spot, you can only apply within 30 days or so of expiry, fill in forms, make payment etc.

If anyone has a problem with your return flight dates it will likely be your airline at check-in

even tho you got a tourist visa, the airline might refuse you to board. You should consider to buy an onward ticket for 15bucks and save you some bad times

Well you're not gonna "on the spot" ask for an extension 😕

First because you don't get extensions at the airport 😮 you get them at the immigration office that serves the area where you stay

Second because most offices won't let you get an extension until you have 30 days or less left on your current stamp

You will be fine, and I doubt the people at passport control will say anything to you when you stamp in, because you're coming here with a valid visa

Come in, get the 60 day stamp, when you are down to 30 days or less go to the immigration office in your area and get a 30 day extension for 1900baht, it will be added to your current stamp expiration date