If you are catching the train to save a few dollars in hotels, then I would say don't bother, because it will ruin your break. Your better option would be to fly and that will give you an extra2 days to spend enjoying your holiday. Chiang mai is so much fun, markets mountains elephants and temples, so is Bangkok which you will enjoy even more. Here it is edgy & thrilling like a huge theme park with a food court always following you. Penang means spices beaches and massages, and Singapore is like the biggest cleanest shopping mall in the world. Your trip sounds wonderful, you have given a lot of thought to it i would say, zurich japan and hong kong will be the highlights and i can see you now in a pair of long tail boats screaming up the river. I would delete Singapore, but that is just me, I am not a great shopper.