Bangkok by train, bus and foot

Arrived back in Bangkok this morning after a pleasant 12 hours journey on the train from Surat Thani. However, after a whole day spent preparing our tandem ride into central Bangkok tomorrow (involving riding local buses to the station -of course no destination is in English... standing all squashed up in a crowded comuter train and walking for miles trying to find Tamsin's house, where we had left the tandem), we are exhausted, dusted up and sufferring from eardrum and lung fatigue.
Have established we will definitely NOT ride on any main road, so small roads by the railway line will have to do, however long it takes!
Wish us good luck!