Hello.

I need to stay in Thailand for 30 days more.

I entered Thailand on single tourist visa 60+30, after 60 days i extended my stay at immigration for 30 more days.

Soon this time will run out and i need 30 more days after that before i go back home.

I planned to cross border and come back with entry 30 day stamp (i am Russian).

That will be my 1st stamp this year, i had another one more then 1 year ago.

Will i have any problem at the land border?

To which country should i go for such a border run? Or should i take a plane?

Share your experience please.

Since you are not on a visa exempt entry now you should have no problem getting an entry. It also helps that you had no recent ones prior to getting the tourist visa.

You can do the entry at any border crossing. Where you go depends upon where you are now.

Not any kind of an expert but I would say to be very sure just take a roundtrip flight to Singapore, you are guaranteed the 30 days on re-arrival.I did that last year, did not even clear Singapore customs or Immi just turned around and back onto the same aircraft.