I am due to go travelling at the end of this year to Thailand, can I make my way to Bali without flying?

I am due to arrive in Bangkok for a few days and then I want to travel around Thailand, Vietnam and maybe a few other places before working my way to Bali. As I will be on a budget can I work my way to Bali by buses or trains etc to save money from flights and if anyone has any experience of this then I will be grateful for your information.