I think it's not a case of either/or. We need both protected bike lanes /and/ more trail connections. The reality is that most destinations are on streets, so if you want to bike somewhere for a reason other than recreation, you are going to have to bike on a street at some point. Case in point is DTSJ where San Fernando allows access to SJSU and other downtown destinations.I think we need to take a step back and see how useful more protected bike lanes would be, in my experience building a bike trail along a river or creek is more useful for cyclists, even if it doesn't get us on some magazine's top 10 bike friendly cities, because people are scared to ride their bikes on the street, and that is fair, at every single cross street is an opportunity for a car to cut you off or hit you. grade separated bike trails like the Guadalupe River Trail and Los Gatos Creek trail allow people to go for many many miles without ever encountering a possible car collision, which is why many people use them. Filing in the gaps in the Coyote Creek Trail, adding a Silver Creek Trail, and better connecting the Penitencia Creek Trail to the Coyote Creek Trail, Silver Creek Trail and Five Wounds trail, and connecting the Los Gatos Creek Trail to the Guadalupe River Trail will be vastly better than adding so many miles of bike lanes on the main streets.
Biking on something like Montague Expwy is scary AF, and adding a bit of buffer is only a slight improvement, people might be comfortable using that as a last mile resort, but not main commute. Even seeing cars going 40mph 20 feet from you can be scary to people. They pretty much need to feel isolated from car traffic. No one wants to be like Liccardo and get hit by an SUV just biking straight, and that is a fear going on any bike lane adjacent to car traffic.
Regarding trails, the one I really want to see is Coyote Creek trail from Berryessa BART to Watson Park under 101. I tried biking to Berryessa BART last week from downtown and while the downtown bike lanes on are pretty good now, the Mabury/Taylor connection to BART is not bike friendly at all and will be a mess with traffic once BART opens. Don't expect anyone except lycra-clad enthusiasts to bike from BART when it opens. The city really failed by not getting this trail connection built already.