I spent about 3 months in SE Asia, mainly in Vietnam, Cambodia, Laos and Thailand. I would highly recommend doing this, you can rent scooters for only 5 USD a day, and travel around a local village and countryside... it's pretty awesome. Even traveling alone, I felt pretty safe in these countries and everyone is so helpful. There are always petty theivery but very little violence. you just have to be smart about your surroundings.
I will be taking a trip to philippines soon to visit friends and tour a lot of the smalller Islands, hope to do a lot of kayaking and scuba.