You’ll have to check whether or not it’s open, but you can walk a nice, wide road up to the Notch at Mt Baldy. Start from Manker Flats.
Most trails I’ve been on in the San G Wilderness are essentially single track trails. For someone concerned about catching a virus etc by passing someone on a trail, you should avoid all of those types.
Perhaps public parks trails would be a better option as they are usually wider for bikers, horses etc. You also may have more room to step off trail to create the distance you desire more easily than a mountain trail.