question about green card

More than 10 years ago, I filed for my sister family to get green card. Now it is almost her time to get green card. I have some questions, if any one here can answer, I will be grateful.

1. Should my sister wait in China and file 485 in China? Or she is better off to come to US now and file 485 in US?

2. If she wants to come to US now? What visa should she apply? Regular tourist visa, I think. But how likely can she get such visa given that she is waiting for green card?  Even if she gets such visa, will be a problem for her to enter US?

Again, thanks a lot.