If you pass the hogan/interview, it's very possible to get to United in 4 years off the street without any prior time here. If you come in with time, you could likely to it in 2.5 years.
ZW/EV/YV won't get near that. Everyone else requires 2,000 PIC while C5 requires 1,000 PIC. CPP/DGI is a lotto ticket and once purchased, you get to find out if you're a winner. If you want a guaranteed winner, go to an American WO.