Subject: Vietnam practicalities

I have received the visa for my trip to Vietnam in November. The problem is, I requested it for multiple entries and got it for a single entry. Based on Judy and Lisa's strong recommendations, I was thinking of taking a trip to Siem Reap, Cambodia, to see the Angkor Wat temples. I was ready to make the decision once I'm in Vietnam, since it seems to be a flat airfare. My thought was to take a return flight from Siem Reap to Saigon that would connect with the flight I've already booked from Saigon to Hong Kong (though it might be nice to have the option of returning a day earlier). Considering that these would be on separate tickets, can this just be considered a transit through Vietnam that would not be a problem with my visa as it is? Most importantly, can I count on the airline to let me board the plane with this visa?

I'd also like to ask about health precautions. The U.S. Centers for Disease Control advisories for Southeast Asia at advise some vaccinations but I'm not sure how strongly. Would people in the know get them for a short trip mostly in the city? They mention getting medication in advance for malaria, and that the Angkor Wat area is of some risk. Does it seem worthwhile to get this when I might be in the area for two days? Thanks in advance,

Andrew Missouri