I've tested this over several days, checking the script against actual travel times and it seems to be reliable. Everything is based on an initial time I recorded when the balloon left Lang.
Whenever the server resets I will probably need to enter in a new base time. All times in your local timezone.
Current Time 7/7/2025, 9:20:54 PM
Base Lang Depart 12/16/2015, 4:12:00 AM
Base Riss Depart 12/16/2015, 4:31:36 AM
Stops at Lang 128267
Stops at Riss 128266
Next Lang Arrive 7/7/2025, 9:53:00 PM
Next Lang Depart 7/7/2025, 9:57:36 PM
Next Riss Arrive 7/7/2025, 9:33:24 PM
Next Riss Depart 7/7/2025, 9:38:00 PM