i just got back from the trip.
typically i went budget for the whole trip.
Generally, for Asians, Vietnam is quite safe. You don't really have to be paranoid and keep your bag infront of you and buckle everything with locks and stuff. (which i saw quite a few singaporeans doing. i even saw a girl tucking her purse in her cleavage)
Accomodation wise, sticking to the ones mentioned in lonely planet or other guide books will do fine even for the budget range. You can get fake (photocopied) lonely planet vietnam in HCMC or those small bookshops in the cities. Accomodation can be found easily near or in the Backpackers district. Prices are quite cheap and affordable. I actually spent half of what i expected to pay for hotels around. Most of the hotel owners speak proper english and language will not be a barrier. Staff there are really friendly. For those looking to go budget, just be prepared that the rooms are just basic, beds (tho some are not comfortable), attached toilet with heater, tv.
As for the food, I'll say after eating street side pho for a few weeks, fast food chain Pho aren't as nice. and its slightly more expansive. Expect to pay 15k to 30k for Pho Bo. Eat at coffeeshop places or clean street side stalls. Coffee there is excellent (I'm not really a coffee person but i drank coffee there everyday). goes abt 10k to 12k vnd a cup? the locals pronounce it as "ca fei swa dar". Try their vietnamese tea too! its quite refreshing for a hot day. it goes by the name of "tra da" say 2k to 6k vnd?
Food here is generally slightly cheaper than singapore. Western food is much cheaper in the restaraunts here compared to sg. But don't expect much because most of the western food i tried are quite disappointing.
Bottled water is widely available. Reputed brands are La Vie (nestle) and Aquafin (pepsi)
Alcohol on the other hand is ard the same price as a can of soft drink. Note: The beers are much lighter here. Tiger is sooo much lighter than the ones in Singapore. I ended up drinking Heine most of the time. Try local beers like 333 (ba ba ba), Biere Larue, Hue Beer, Hanoi Beer and Halida beer. The others just taste like water. Their cocktails goes for abt ~60k vnd. But they aren't really nice.
Transport wise, try to stick with the reputed travel agencies. Try Mailinh and pueong trung (sorry i forgot how to spell but they're recognisable by their big orange buses) for trips between cities. Sinh Cafe also offers such services at an afordable price. Also, the you can get your train tickets easily at the train stations. Just write down the start and end destinations and what kind of seats/sleeper you want. They speak english. For travelling within the city, you can always hail a cab. trust the Mailinh and Vinasan Taxis (its quite easy to spot because they're all around). Its pretty cheap with a flag down rate of 9-12k and 10k increase for every km. Do not try others because they tend to cheat you with rigged meters or taking a longer route. Also some of them have logos that look similar to Mailinh.
As for travel agencies, there are many around if you look carefully ard the backpackers district. But i used Sinh Cafe most of the time for their ability to speak english at all the branches.
If you need info about the specific cities and what to recc, do email me at
jonathantee89@gmail.com
hope this helps! cheers!