Laos and Cambodia for 3 weeks

Hi,

I'm going to Laos and Cambodia for 3 weeks. I arrive in Bangkok on 2 April. I will probably go to northern Laos first (Vientiane, Vang Vieng, Luang Prabang) and then will be heading south (Pakse, Don det), to Cambodia (Siem Rep and Phnom Penh). I stilll need to figure out how to best get to Laos. As I don't have much time and would like to visit a few places, I need to try to save time for travelling.
Please let me know if you are planning to go to Laos and/or Cambodia and would be interested in travelling together for a bit :) Also, any recommendations for a places to stay in and worth visiting are more then welcome!

Cheers
Agnieszka