Done a border run last year was easy just the overnight train is not the best nights sleep my girlfriend border run being Thai was about 50 baht and mine 1700baht plus hotel 3 nights but all part of the adventure 👍.
I done 60day visa done the 30 extension then done a border run for 3 days came back with a 60 day extension then back ,another 30 days at ministry but left with 7 days still on visa no problem,