you mean enter at Pakard an heading south from Batt to KK, correct
or heading form KK to Batt to Thailand?
have used that border many times, great, easy few times ,( driving my own thai car) have left Cambodia an driven into Thailand and forgot to get stamped out of Cambodia or into Thailand and had to turn around when i realized was driving on the "other" side again.
its a 90 minute ride in a shared taxi from the border to Batt
BUT to get to KK you need go to Phnom Pehn and than head south, the road between Batt , thru the Cardamons , is not open, ( friends tried to go thru on motorbikes last month)