[Hi Eileen,
Ask away! The trip was fantastic - I'd quite happily go again! I took dollars only - you can change to Vietnamese dong in the hotels but most people are happy to take dollars. In Cambodia they prefer dollars but will give you change in Riel as they don't have coins for anything under a dollar. The hotel in Can tho will take dollars but outside of the hotel they only took Vietnamese dong. After your stay in Can Tho you travel by bus to Chau Doc about 3 hours if I remember correctly then get on a speedboat and travel up the Mekong Delta for 5 hours to Phnom Penh - you have to get off at the Vietnam border control for your exit visa and then less than 5 minutes later back off for your Cambodian Visa to be checked - wait till you see Cambodian Passport Control! Nothing bad but its one of the more remote border controls I've seen! Travel plugs were a bit odd, I was able to use a British plug in Hanoi! a bit of a surprise but had to use my adaptor, once with the two round pins and in other hotels with the two straight pins.
Any other queries just ask - I could talk about this trip forever!
Best Regards
Jacqueline