My wife and I will be taking an overnight train from Bangkok to Chiang Mai. We would prefer train 13 to see more on the approach to Chiang Mai. I have seen information that train has only single berth sleeper compartments. Is it possible to book a two-berth sleeper for that train? if not, are there adjoining berths connected by a door? How do I make sure we are together in our booking? Does the number 1 train offer much opportunity to see the landscape heading into Chiang Mai? How can I make sure we share a berth on that train?