Newbie, here. This has probably been addressed many times but I have no idea how to search this topic:

I want to fly from Rio (GIG) to the San Francisco, one way. Most flights have 2-3 stops and are in the $1000-$1100 range.

However, when I click on "include other airports" one option comes up with 4 stops for just $630. On Avianca. Under flight details, the final stop is SFO, with an 8 hour layover there, then a 37 minute hop to Monterey on United (a 2 hour drive past SFO). If I leave that option off, with SFO as the final destination, it comes up with the same flights (minus the hop to Monterey) at $1035!

1. Can someone please explain this craziness to me?

2. What happens if I take the 4 stop option, but don't take the final leg?

3. If I check baggage, but never get on that final leg, will I be able to pick it up in Monterey? Or, will I need to get it through customs at SFO, anyway? Then, I could just take it home from there.

Seeking your great wisdom...

Dave