Just to hit the highlights is you are in a preliminary planning stage. We cut our trip short from the planned 77 days to 54 because of the corona virus. Originally, we flew to Bangkok, then Krabi, Thailand, Singapore, Bangkok for 1 night, Sukathai, Chaing Mai and Chaig Rai, Thailand. Then Mekong river cruise to Luan Prabang, Laos, flight to Hanoi then Ha Long Bay, Sapa, Hue, Hoi An, Vietnam. What we cut was Ho Chi Min City, Phem Penh, Ankor Wat, and a couple of end days in Bangok. Overall, though we wanted to go slow, we planned it too slow, unless you really like the culture in southeast Asia. Lots we read talked about how wonderful northern Thailand was and how 30 days in Vietnam would be too few. We were not that enamored of either, though Mark loved his 5 day cooking school in Chaing Mai, Thailand. For us, what not to miss are Bangkok, Singapore, Hanoi for Ha Long Bay, Hoi An, and of course Ankgor Wat. Just remember to leave extra time at the beginning for the very long jet leg recovery. Also plan for the heat, with sightseeing mostly in the morning and really Ankgor Wat is too hot by the end of February and leave Hanoi area for late February or even March. We have now been to two beach areas in Thailand, Koi Samoi and Krabi, and we liked the Krabi area better because of the karst islands, but then we are not beach people.
Taxi, bus, train and even most airfares were very cheap. The exception was the airfare from Luan Prabang to Hanoi. Visas are required for Laos, Vietnam, and Cambodia—all available when you get there and in the $30-55 range. Fares are quoted in full write up.
We had saved up our points and free nights on IHG and Marriot credit cards and those paid for 14 nights of the trip in Bangkok, Krabi, and Singapore. Krabi was so cheap we should have just saved the points. Eliminating those free nights we averaged $53 a night. We did stay in one hostel, in a private room, for $40 a night. I think budgeting $55 a night outside of big cities would work, $70 in cities except for Singapore where $110 would probably do. Almost all of our hotels provided a big, buffet breakfast—a few only did that if you booked direct. We usually ate our main meal at lunch and really didn't splurge often. For dinner we sometimes just had ham, peanut butter, fruit, etc. as 95% of our rooms had a refrigerator. Overall we averaged $40. a day for food total for 2, not including alcohol. This is probably less than normal folks would spend (maybe $10 less) and more than if you ate a lot from street vendors, which we did not do.
Admissions to temples etc. were very cheap. Our biggest recreation expenses were the Ha Long Bay cruise, Sapa trip, and Mekong river cruise.
We had read that malarial mosquitoes were present in Laos and border areas. We were taking doxicycline for part of trip but it was totally unnecessay in winter. We never saw a mosquito before Hoi An, and that is not a malarial area. All the hotels provided bottled water daily and if you needed more it was very cheap. We had our SteriPen UV water sterilizer with us and only used it a few times. Mostly we did laundry in the sink as hotel prices were still quite high. In most places you could find cheaper rates within a couple of blocks of the hotels, and the Holiday Inn Express hotels all had coin operated machines. We checked for bedbugs a every new hotel and never found any. We were pleasently surprised that almost everywhere the mattresses and pillows were great. We traveled with two small backpacks and 2 carryons which we mostly checked as carryons in Asia usually can't be over 15 lbs though we didn't see much evidence of anybody weighing them. Usually they were included in fare and not much if not.
We did plan ahead for hotels and such for our first half of the trip. After that I made reservations a week or so in advance—7 days or more usually could save some money. I will say this, I think that when the social distancing for the virus is over, and the over 60 crowd can travel again, that they will with a vengeance unless their finances were devistated by the market fall. So you might have to do a lot more advance planned for southeast Asia. Happy Travels soon I hope. Vicki