There are many choices for public transport. It is easy and cheap.
The Hop On Hop Off Bus is a good way to get an overview of Kuala Lumpur, look at the Hop On Hop Off website for prices and schedules. The Hop On Hop off Bus is very tourist and children friendly.
The local RapidKL ALL-DAY ticket which visits all the same places as the HOHO via various bus routes and more, like Batu Caves , although not in a circular route. Expect to pay 1myr for the the All-Day Local Bus, about about 2myr on the All-Day Trunk Bus or All-Day City Bus and 5myr for a All-Day Express Bus. The ALL-DAY ticket will give unlimited rides on the routes in the same service (Local, Trunk, City or Express) for the whole day.
Buy the tickets on the bus or visit the Rapid KL Website.
Trains, Monorail and Light Rail Transport LRT
The train system in KL is fairly modern and efficient. Many of the lines do not interconnect and there is limited integration between the lines.
The KL train system are: KL Monorail, Star LRT, Putra LRT, ERL and KTM Komuter. Then there is also the KLIA Express which goes non-stop between KL Sentral and Kuala Lumpur International Airport.KLIA1 and KLIA 2 (budget terminal) are now interconnected.
There are two trains service to the airport:
1. Non stop KLIA express
2. Klia transist (stops at few stations)