Last night after Andrew finished work, we took a quick cycle out on the Bay.
This cycle picks up from the same location as the Alviso Slough Trail, except instead of heading out on that trail, we cycled to the Mallard Slough Trail, a smaller trail to the east pictured in orange on the below map:
From the end of the Lower Guadalupe River Trail, turn right and follow Gold St-right on Catherine St-left/straight onto State St-right on Spreckles Ave-left on Grand Blvd and left again to stay on Grand Blvd and follow it across the train tracks and round to the car park and US Fish and Wildlife Service buildings by the bay.
The Mallard Slough Trail is 3.3 miles in total, or you can cut across to the Alviso Slough Trail via a bridge over the railroad tracks, and take that trail back to the Alviso Marina County Park parking lot.
It is a nice, well maintained trail, with vista points and information along the way.
We decided to follow the Mallard Slough Trail, then cut across to the Alviso Slough Trail to go back to the Alviso Marina County Park parking lot, and then followed Hope St-left on Catherine St-right on El Dorado St-left on Moffat St-right on Gold St (the alternative to taking the Public Shore gravel path back across the tracks), and then we were back to the end of the Lower Guadalupe River Trail.