It can travel very easily in the Thai capital (touktouk, taxis, buses, underground ...) and out of Bangkok there are also many buses or taxis but do not forget the train ! Very cheap, it will enable you to discover the country around Bangkok.
And 80 km from the city is the site of Ayutaya I really advice you to visit it. Taking a train, spending the day will be one of the most beautiful day that you live in Thailand !


Bangkok station