My best friend and I are planning a December trip to backpack through Vietnam, Laos, Cambodia, and Thailand. Is $500 enough as pocket money? Would 1 week be enough for us to visit the hot spots of all 4 countries? Is there a train that travels through all these countries and how much would it cost us? How much should we set aside for lodging? Do you have any suggested itineraries? I'm from the Philippines and the only points of entry that I know are: Bangkok, Thailand and Ho Chi Minh City, Vietnam. Your help would be very much appreciated 