The MurrayGuesthouse.Com have special offers for tours from Phnom Penh to Chau Doc, then to floating markets in Can Tho. You will end the trip in Saigon.

On other direction, you can start the tours in Saigon and travel to floating markets in Can Tho then move to Chau Doc town. The express boats will bring you to Phnom Penh.

We do not recommend the short tours (2 days 1 night), but in case you have shortage of time, just consider the short ones.