Laos is my personal favourite, much of the country is rural with a laid back approach, the roads are quiet. I'd say it's under developed which gives it charm, although the touristy spots are now getting overly commercialised, it's well worth a visit. 

Chang Mai to Vientiane

Jan, Peter, Gavin and Keith. If I were to pick one tour to repeat again, this is it, an extremely good route, stunning mountain scenery, starting from Chang Mai heading east across north Thailand then crossing the river border into Laos. Take a lazy river boat down the Mekong river and disembark at Pakbeng and out into the wilderness. A wonderful ride to Luang Prabang, good hills and scenery. Then continue south through more stunning scenery, there's a little known Chinese trucker's guest stop, fabulous. More...