回复：how long does it take to ...

1. You are able to go back to China before filing I-485. But a entering visa is needed for back to USA.
2. During I-485 petion period you need a AP or H-1 visa to back.
3. If go through Labor certificate, It takes about 2-3 years to be able to filt I-140/I-485 in current situation in California.
4. I think that to buy a condo at San Jose right now is a food chose. Anyway You are not going to lose money.