I'm intending visiting Vietnam and Laos next year after returning home last week spending 3 weeks of my 5 weeks travelling around Cambodia. I was going to slip over to HCMC from Phnom Penn for a couple of days but decided not to as I hope to visit next year. A few travellers commented that there are many locals in HCMC intent on trying to scam tourists. These can easily be avoided by using reputable travel agencies in respect to travel and simply saying no thanks to anything that sounds too good to be true because it probably isn't. The only other advice I would give is to use common sense when out late at night. I'm 52 and would rather walk the long way to where I'm going where there is lighting and/or many locals rather than chance my arm walking down a narrow paved/dirt road with a lack of lighting/locals. I apply this rule when I am anywhere in SE Asia. I travelled around Cambodia by myself and met people on buses, some of whom I subsequently socialised with and/or travelled with to my next destination. Safe travels. Enjoy.