As I sit in the shadows of the flight paths at SFO...
From Eugene, your only direct options here in July are to SFO (United--daily) and OAK (Allegiant--certain days only).
To get to Monterey, you need to go EUG-SFO-MRY, or a longer connection at LAS/LAX/PHX/DEN.
To get to San Jose (closest Bay Area airport to Pasa), you need to go EUG-PDX-SJC, or a longer connection as above plus SLC/SEA.
The drive from SFO to Pasatiempo isn't bad, just take 380/280/85/17 and stay off 101. I do the first three legs of that drive every day, figure 90 minutes or so.
The drive from OAK is similar (880/17), and Allegiant has some really cheap fares, but I'm in the airline/transportation industry and honestly don't know much about them.