Hi Kelster6911 ,
After doing some research, we have opted to do Vietnam in 2 visits (as it is such a large and diverse place) and it is difficult to match climate and weather in North and South. The weather in and around Hanoi is not too great when it is at its best in the South.
We are in Vietnam and Cambodia at about the same time as you are in Goa - we've opted for a change this year after visiting Goa for the past two years.
There are several "gateways" to Vietnam but no direct flights. Like Fiona, we have opted for a route via Bangkok. The reasons were many but we like extra space on the aircraft. We are flying Business class on EVA Air for about the same cost as PE on British Airways. We frequently use EVA PE (elite class) on this route - 38" legroom for a very good price.
Bangkok Airways are always a great option locally and they have flights to Saigon - which was appealing to us.
We have opted to do:
Saigon - a few days, because it is apparently unmissable.
Mekong Delta - 2 nights
Saigon -1 night
Phu Quoc Island - 1 week - a shortish trip by air from Saigon and after various indifferent reports about some coastal resorts we thought this looked great. Could not find a poor review of the island or the chosen hotel (La Veranda)
We will then return to Bangkok via Saigon and Siem Reap (taking a few days to look at Ankor Wat etc.).
The Next trip (GBP / $ exchange rate allowing!!!) will probably be Hanoi, Halong bay and TBA in the North of Vietnam, returning via Laos and probably using Bangkok as the gateway again.
Obtaining a Vietnam visa was painless and quick (can't remember the cost but thought it was a little OTT). For Cambodia you can get an e-visa (government site allowing as it seems to "fall over" pretty frequently). This is all online (you need a good quality jpg passport photo). It currently costs $25 per person and takes about 24 to 48 hours.
Will post a TR of places and hotels when we get back in March (Fiona would give me grief if I didn't), so if you can wait we will be only too pleased to provide any help and info then.
Enjoy Goa!
Enjoy planning Vietnam!
Peter