Hello Maggie, 5 days is plenty to see C/mai and it is a wonderful place with great people, make sure you visit the canal in the centre at night to feed the fish,,brilliant,,,elephant trek is a thing not to be missed you will talk of it for years to come also you get a raft trip on this,,,,as for a train its a 12 hour trip tp bkk but great views,,,take a train one way and flight the other its cheap enough,,,have a great time,,