Looking to do the cave trek, and leave from Hanoi. Loose itinerary is Siem Reap, Hanoi , Dong Hoi, Hanoi, Halong, then back to Hanoi. Is there a better way ( quicker, cutting out Hanoi on the front end) to get to Dong Hoi. All I can find are flights with long layovers. Seems best to explore Hanoi b/t Dong Hoi and Halong bay.