Hi pearl,
usually for PNPG & Nursery, 1st 2-3 days are orientation days for the child to be familiar with SJCK. There'll be no sch bus services for PNPG & Nursery, so do make necessary arrangement to have someone be with the child in sch during those days.
As for sch bus, here's what we did help our boy.
1) Opening letter box
go down to open your letter box during evening or afternoon time where you'll see kindergarten/pri sch children boarding/alight from sch bus. Bring along your gal and explain to her what those children are doing. (avoid sept/nov/dec sch hols)
2) Nov/Dec holidays
daddy took DS to take SBS bus/MRT quite often. Teach him how to enjoy the scenery through the glass window, ie spotting familiar landmarks, observe what ppl are doing, types of vehicles that passes by, etc. Get used to having strangers sitting next to him.
3) Prep talk
4) actual 1st day taking sch bus.
By then, my DS is quite ready to take sch bus by himself. In fact he was looking forward to it. But bus uncle did tell us that he sobbed a bit on the way home, cos he was the last few to be dropped off. The bus uncle and auntie encouraged him, saying that he is a good boy and uncle will be bringing him home soon.
My 2nd son starting with SJCK PNPG next yr. He's so used to seeing gor gor boarding/alighting sch bus that he actually wanted to follow along. So i'm quite sure my 2nd boy will be okay with taking bus (esp when he will have his gor gor with him as well)
Not sure if it will work with your gal. Cos it's normally easier to get boys interested in buses/cars etc. Give it a try and let us know how things goes.