During the Idul Fitri public holiday on 2011, I manage to travel over land to Singapore, Cambodia and Vietnam. I am aware that my itineraries is not very effective but this is the only way I can lower my cost. If you can get cheaper direct flight, I strongly advise to use the direct flight.
So, here is my 11 days itinerary starting from Jakarta - Batam - Singapore - Phnom Penh - Siem Reap - Phnom Penh - Ho Chi Minh City - Muine - Na Trang - Hoi Ann - Danang - Hanoi - Jakarta.
Day 1 : Jakarta - Batam - Singapore
Because it is public holiday, the flight ticket Jakarta to Hanoi/Siem Reap/Singapore is very expensive. So the best way is to take flight to Batam then take a ferry to Singapore.
Day 2 : Singapore - Phnom Penh - Siem Reap
In consideration of budget and limited time, I have to travel to Phnom Penh instead of direct flight to Siem Reap. From Phnom Penh I take an afternoon bus to Siem Reap so I have time to visit Killing Field, Phnom Penh
Day 3 : Siem Reap - Phnom Penh
I am not a historic person, so I just bought 1 day pass to Angkor Wat and in the evening taking a night bus to Phnom Penh.
Initially we plan to take a night bus from Siem Reap direct to Ho Chi Minh City but when we arrived in Phnom Penh there is no bus direct to Ho Chi Minh City. Most of the bus stop in Phnom Penh only, so we have no choice. The only bad side was we couldn't book bus Phnom Penh - Ho Chi Minh City in Siem Reap. Hopefully we can get ticket in early morning.
Day 4: Phnom Penh - Ho Chi Minh City
The reality is not get along with expectation, we only manage to get the 10.00am schedule, what a waste time. Eventough it means we have few hours more to explore Phnom Penh, I have to cancel some plan in Ho Chi Minh City.
Day 5 : Ho Chi Minh City - Mui Ne
In the evening we will travel to Mui Ne by Sinh Toursit Bus, so we take a half day Chu Chi Tunnel tour.
Please book your bus ticket in advance.
Day 6: Mui Ne - Na Trang - Hoi An
We hire half day jeep to explore Mui Ne, then in the afternoon we take a Sinh Tourist Bus to Hoi An, stop over in Na Trang for a while.
Day 7 : Hoi An
We have a full day to explore the Unesco World Heritage, Hoi An so we take it easy, more relaxing.
Day 8: Hoi An - Da Nang - Hanoi
Da Nang is the last city we visit in our over-land trip, from this city we will take a plane to Hanoi. We can reach Da Nang by bus, but we have to take another bus from Da Nang city to Da Nang airport. This is cheaper but a bit troublesome and take more time.
Luckyly the hotel inform us about car rental, to my suprise the cost is not that expensive. With this car we can make a few stop in Da Nang to visit some beautiful place before he drops us in airport.
I decide to take a plane from Da Nang to Hanoi because time consideration, there is no direct bus from Hoi An or Da Nang to Hanoi. We must make a stop in Hue first and the journey Da Nang - Hue - Hoi An take about 16 hours. We don't have that much time, moreover the flight ticket is quite cheap so it is really the best choice.
Day 9 : Halong Bay, Hanoi
Halong Bay is the highlight in our Hanoi trip but I only able to allocate 1 day to visit it, so the best way is to book a one day trip Halong Bay tour from local tour agent. With this arrangement, we still have some time in afternoon to explore the old city Hanoi.
Day 10 : Hanoi - Singapore - Batam
Our flight to Singapore is in afternoon, so we have few hours to explore Hanoi on foot.
Then from Singapore we take a ferry to Batam. There are a lot of ferry Schedule to Batam.
Day 11 : Batam - Jakarta
This leg is not necessary, I take this only because this the only option to get the cheap airline ticket.
I hope this itineraries can help you to arrange your own itineraries.