sporeans dont't need visa to go to KL. if you have to, go to the Msian embassy.
it is advisable not to take stroller on the streets, the pavements there are pretty uneven. except if you want to use it in the shopping centres. All the LRT stations have stairs. Not all the stations are interconnected, some you will have to walk some distance to join another line. I used the sling to move around previously.
I always go back to KL via the Transtar bus which is comfortable. their office is at the Lavender road. very convenient if you want to travel with kids. now you can get there by flight. tickets are cheaper now.
one thing is to be careful of the taxi drivers there, especially the white shirts one with long queues of taxis. they will charge exorbitant prices.