oh... u might be better off on overnight trains then.
when i took the 1am coach, i arrived at 4.45am at pudu. trains
leave JB at 11 (often delayed till 12+), arrive at 7+.
no need booking. there are so much more services to KL that you
don't have to worry. you will never have to wait more than 90
minutes maximum, sometimes you can even opt for immediate
boarding.