Train 70 departed Udon a few minutes late, due to the train in front arriving late from Bangkok, and not being ready to return until our departure time.  Still we were only 25 minutes later into Bangkok station.  That's the nearest to on time I've managed.  I was lucky on MRT and Airport rail link timings and actually managed with 2 minutes to spare to get on the 8am Pattaya bus.
As a result I was in the hotel before 10.  Hope the rest of the connections on the trip go as well