Southeast Asia

Wendy. Travel in Vietnam is quite simple for independent travellers. In some places it may make sense to take a short tour if you have limited time and want to simplify logistics eg. in Halong Bay or the Mekong Delta where a lot of people like to explore the waterways. My favourite city is Hue in the centre of the country.

I would recommend getting a copy of Lonely Planet as it gives good advice on possible itineraries as well as in country transport.

Australians must organise a visa in advance through the Vietnames embassy or one of their consuls. I believe that this also applies for US citizens.

We have traveled independently in SE Asia and found it to be wonderful!
The two countries we have explored are Thailand and the Philippines. We made sure we did our homework very thoroughly, researched on TripAdvisor, read guidebooks, and thought long and hard about the kinds of accommodations we would stay in. IMHO it is not a part of the world for low-budget lodging - decent lodging the one thing I would recommend making sure you budget a good amount for. We stayed at a very nice hotel in Bangkok and were glad we did - the city is amazing but it was gritty and very overwhelming and I was happy to have a bit of a refuge to go to at the end of the day.
The rest of the time we had a car and based ourselves in Phuket, which was a home exchange. We also drove all around the edges of the Andaman Sea to many towns, villages, and temples. No reservations, just finding places as we went along. Took ferries out to some of the islands and then longtail boats from there to even smaller islands and offshore reefs for snorkeling. It was all very doable and most people who deal with tourists speak English enough to do business with them - there are lots of British and French tourists around so if you speak English and or French you can do fine. I know that this is also the case in Vietnam - more French than English though.
Most SE Asian countries have the equivalent of a tuk-tuk of jeepney type service that is like a taxi/bus. Tuk-tuks will take you wherever you want to go and jeepneys have a route. They aren't hard to figure out - you just have to have the guts to zip in and out between traffic and trust your driver. It's quite exciting!
Sorry I can't give you more specific advice about your three target countries but you asked about SE Asia so I thought I could at least share this little bit to get you thinking.

First off, the best time to visit depends on the weather! December-February are usually best because there's little or no rain then. I was in Vietnam on day trips from a cruise. Saigon is pretty manageable on one's own. The other two days were with a small group (4-5 people) and private guides. The best food I had (strict vegetarian) in SE Asia was in Vietnam. I flew to Siem Reap and spent 3 nights to see the temples of Angor (wonderful) with a private guide and driver (very affordable). After Siem Reap, I really had no desire to see more of Cambodia. I love Thailand! I didn't find Bangkok "gritty" - in fact I thought it was pretty clean. Loved wandering the markets, gorgeous temples, friendly people, good food. I stayed in a little quirky hotel in a residential neighborhood, great location, with all the amenities (A/C, good shower, good breakfast, coin-op washer/dryer and more). The north is even more interesting, beautiful and better climate - not humid, cool nights. For Chiang Rai I had a private guide with car for 3 days, then on my own in Chiang Mai. So much fun! Except for Vietnam, I was traveling as a single woman. I used Trip Advisor for most of my planning (and a friend who'd been).

Wendy, our family is going to Cambodia this summer and we're using Indochina Odyssey Tours to do a private tour (family of four) of the Siem Reap area. The price is extremely reasonable and I know someone who had a great experience using them. I know you didn't ask about airfare, but I notice you're in Toronto and wanted to mention that we got a great deal with United. Toronto to Singapore with a week long stopover in Tokyo for $1250! We're using Singapore as a base, as airfares out of there to surrounding countries are very cheap.

Thanks for the advice. I think I am leaning towards independent travel in Vietnam, with a small tours in some areas. When doing small independent tours ( 1 or 2 days) do most people book them in Vietnam, I will be staying at hostels and smaller hotels and usually find they offer tours or know of tours. For the rest I have not decided on how to travel, I am thinking a bit of both.

Never thought of Singapore as a base. I was thinking that Thailand may be the best to fly into but will look at options. Maybe even Hong Kong as a stop over.

Wendy

Singapore is the most expensive place in Southeast Asia! Food, transportation, hotels, everything. Unless you really want to see Singapore (hardly my favorite), avoid it unless you are just changing planes. I had a Singapore sling there that cost me more than a hotel night and 2 Singapore slings (I was only going to have one, but it was happy hour, so who could refuse a free one) in Siem Reap.

If you are planning to go to Cambodia just for Siem Reap (Angkor), then check prices for flights carefully. I went when on a trip to Thailand, and the plane fare from Bangkok was huge compared to flights to other destinations but it was my only option.

Wendy, Hong Kong would be a great place for a stopover if the flights/finances work out. It's a fabulous city to explore for a few days. Singapore might not be of interest--we're going so youngest son can see the proboscis monkeys at the zoo and I want to see the Gardens by the Bay, and it was named Lonely Planet's top destination for 2015. I'd love to see your itinerary when you finalize it! Also look at Explore adventure tours if you haven't already. We've used them 5 times (for the Middle East and India) and they are a very good value.

Martha I have used Explore in Morocco and loved them. They are who I am thinking of using if I do a tour. I do not have an outline yet, still working out time lines. I am off school for the year so working two big tips 2-3 months each. In addition to Southeast Asia I am also looking a trip that includes Jordan, Turkey, parts of Eastern Europe as well as Paris. Last time I was there I had not discovered my love of museums and spent my time in the Louver looking for the Mona Lisa and that was it. Now I plan a day or two exploring the museum. I have from Sept 2015 to the end of Aug 2016 to travel. I cannot be gone the whole time but it allows me flexibility.

Well that sounds fabulous! We used Explore in Turkey and Jordan/Syria (where I bought an 'I heart Bashar al-Assad' t-shirt which I won't be wearing anytime soon). If you go to Turkey hopefully it will include a few days sailing on a 'gulet'. We found Turkey and Jordan to be pretty magical. Nothing like doing a camel safari out in the desert, sleeping under the stars and waking up to bread which has been cooked under the sand!

Southeast Asia is an AMAZING place to travel. There are some great sites (and some not so great) I would avoid Bangkok and Ho Chi Minh City. Here is a great blog I've come across that describes Cambodia and Vietnam in detail with lots of great pictures (also some great guest houses/hostels to stay at:
http://togetherinthailand.com/vietnam-trip-nutshell/

Northern Vietnam is pretty cold during February, so if you want to see Ha Long Bay, a better time would be April.

Hope it helps!

Weather is a biggie there, so make sure you're familiar with weather patterns at the times of the year you're considering, before you pick dates.

Just got back from Myanmar, Cambodia and Vietnam. I was on a private tour.

I went to Siem Reap for Angkor Wat and then picked up a Mekong River cruise from Phnom Penh to Ho Chi MInh City. I don't feel I need to go back to Cambodia. Angkor Wat was definitely worth visiting and I recommend getting a guide there to get the most out of the various places.

Getting to and from Siem Reap can be a bit of a challenge. We flew there from Bangkok on Bangkok Airways (an airline which I recommend highly) and from there to Phnom Penh on Cambodia Angkor Air - there's also a reasonable bus service now between the two which takes 6 or so hours - it's a new one with better buses. Or you can find private car service (ask your guide to help with this). Travel within Cambodia seems to be a bit of a challenge. We applied for visas on line before we went (evisa) and I recommend this as it saved us a long line up upon entry to Cambodia.

I think Vietnam would be a good place for you to start - we barely touched the country and it seems to be booming, at least in Ho Chi Minh City. You need a visa before you leave. We applied for our visas in advance. You do not need to send in your passport - just an application form which you can get online, and some photos. Our visas were mailed back to us and we paper clipped them into our passports.

The weather in Ho Chi Minh City was about 34 degrees Celsius last week. It is dry season and we didn't have any rain. I think this is a good time to travel. We were told that it rains every day in HCMC in rainy season. Other parts of the country may differ so you need to check this out in advance.

I was bothered quite a bit by mosquitoes, although my travel companion didn't have the same problem.

If you do go to Vietnam, be aware that they celebrate New Year at the same time as the Chinese do and it's a major holiday. Many of the shops and restaurants were closed last week - many for at least a week, so this made it a bit difficult for us as visitors.

Thanks for all the advice. I still have not made final plans about when to go. Think jan or feb starting in Vietnam then moving to Cambodia and Thailand. A tour for sure in Cambodia but the rest is still up in the air.