I'd go for it... If the rolling stock is adequate and the schedule looks good to actually enjoy the scenery. I'd even go for breaking the trip up into several days and spend some time and money in hotels along the way. One of my ambitions was to take a train from KL (where I had some contract work) to BKK (where my contract had lapsed, but I was living). I wanted to see the sites and experience a train ride. Never again. The sites were amazing, but the trains were dismal, in Thailand and Malaysia. Malaysia's trains were better, but no place to even sit because it was a holiday. By the time I got to Bangkok, I was so ready for the trip to be over. Sadly, a lot of the truly scenic areas in Thailand came when it was dark outside. Live and learn. Even now, one of my favorite weekends in Thailand is to take the dilapidated train on the death railway to Kanchanaburi. But that's just 3 hours (or so). Even that gets a little old after a couple of hours of sitting on planks. But the history... I'd love to take a leisurely train ride from BKK to CM or CR or 3 Pagodas or Hat Yai. But not on a cattle car.
