Here are three suggestions that I think are key for a smooth trip:
1) Try to get there a day early. Use that day to sleep and get your bearings.
2) Plan on using hotel laundry services on a daily basis. If money is an issue, choose a more moderately priced hotel where laundry services are likely to be cheaper.
3) Pack comfortable, washable clothing. Suggestion number two will allow you to pack more sensibly. You don't want to be dragging tons of luggage with you through airports. In Vietnam I found that my husband and I needed only casual clothes. I brought one slightly nicer outfit for the giving and receiving ceremony that involves government officials and sometimes the birth parents. But even in that case, I tried to keep it simple.
Keeping these things in mind, I advise against packing big, bulky items like strollers. In Hanoi, I would never have used a stroller because of the chaotic, unregulated traffic. While it was mostly mopeds and bicycles, we found it tricky to cross the streets, and it would have been impossible with a stroller. If you get there and feel lost without one, buy an inexpensive stroller, then donate it to the orphanage.
I recommend using a front baby carrier unless your baby is much older and too heavy to carry with you for two weeks. Unfortunately, even though I made a big point of needing either a front pack or back pack, I ended up forgetting to take either and was forced to buy one from a Hanoi street vendor. It was shocking pink with a funny-looking bunny on it, and my husband felt somewhat ridiculous using it, but it was functional and only cost $8.
Bear in mind that you can buy baby clothes and other items in Vietnam if you need them. The one exception is disposable diapers. I brought 180 diapers, was there two weeks and used almost all of them.
Another key piece of advice: See a pediatrician before you embark on your trip. Ask the doctor for prescriptions to combat scabies, and an antibiotic in case your baby has a respiratory infection, which is quite common among babies who have spent time in orphanages. Get enough scabies medicine -- Elimite Cream -- for the baby and for yourselves. One treatment is usually enough, but you don't want to return home with scabies. You might also get medicine for conjunctivitis, a common eye infection that babies often pick up in orphanages that you'll want to treat immediately. In Vietnam we found a Western-style medical clinic for a checkup when our daughter was sick. The physician ended up prescribing the same antibiotic that we had already gotten from our pediatrician at home. Before you pack, check the Internet for weather reports. In Hanoi, where we spent the first 10 days of our trip, it was winter. And despite the fact that it's in Southeast Asia, it was chilly -- in the 50s -- and very damp. In Ho Chi Minh City, where we spent our last four days, temperatures soared into the humid 90s. In tropical regions, it's important to remember that you'll be in air-conditioning most of the time and will spend very little time outside. This means that you need to bring warm things for the baby to sleep in and at least two receiving blankets. The trick to packing is making sure you can layer your clothing. Sweaters and sweatshirts can be used for both you and your new baby. Everything we brought was cotton and easy to laundry. Avoid items that require dry cleaning. I pre-washed all the baby's new clothes.