The paved trail between Wardlaw Park and Hanns Park follows Blue Rock Springs Creek and mostly flat.
The Blue Rock Springs Trail joins several parks along Blue Rock Springs Creek. It's an interesting suburban trail that offers a mix of trail surface, terrain and environment. This means you can make pretty much whatever you want out of the trails here.
The westernmost terminus of the trail is Hanns Park. Numerous shady Eucalyptus trees provide ample cover for the picnic benches here. A natural hiking path heads south of the main area through a small valley before emptying into an adjoining neighborhood. The outline of a home or building foundation sits in a small bowl surrounded by houses.
Several bridges are dotted along the trail where it crosses the creek.
The main trail heads west from the parking lot, following the eponymous creek. Because much of the trail follows the stream there's little elevation variation. On top of that, the the surface is paved. A few well constructed bridges make quick work of stream crossings. This section of the trail would be considered ADA accessible. Houses dot the ridges overlooking either side of the path.
Wardlaw Park lies near the middle point of the trail and typically has better parking than Hanns Park. There's an off leash dog park here if you have a canine companion who would like to socialize with some other dogs. A bridge connects the park with the trail since they lie on opposite sides of the creek.
Heading east from Wardlaw the paved trail continues. If you continue along the paved trail to the very end you'll find yourself in front of a locked gate with a golf course on the other side. This means you've gone too far. There is a trail junction a short distance behind that marks the beginning of a new trail type. Though there are trail posts that mark the spot where the junction resides, the rougher trail that connects is fairly obscure, at least compared to a wide paved path, and so may be easy to miss.
The natural trail overlooks the Blue Rock Springs Golf Club and occasionally gets close enough that you could have a conversation with golfers teeing up.
The single track hard pack path starts climbing uphill to work its way around the golf course. As it does so vistas are opened up to the north and east. The Sulfur Springs Mountain ridge in the distance serve as a backdrop for the well manicured golf links below. The trail does not venture far from the boundary with the gold course, so don't be surprised if you clearly hear conversations between golfers as they tee up.
The rough trail portion descends from its higher perch as it empties out onto Lake Herman Drive. Though the gate here can be locked, it mostly likely remains unlocked during "normal" hours.
Once crossing the road the trail splits into two directions and may, or may not take on a new name. To the north, the trail follows along Columbus Drive before ending in about a mile at Blue Rock Springs Park. This park is not always open and has an entrance fee. According to the park website, a trail heads up Sulfur Springs Mountain for some views over Vallejo and the napa River.
According to signs at some trailheads, the trail split to the south goes all the way through to the shores of the Carquinez Strait.