The dock is across the lake from where the bikes were found. A long walk, silly to do so if you had a bike. There are two docks, one for fishing, one for boats. You can see across the lake pretty well - enough to probably identify someone you knew.
Where the bikes were found, the trail is bound on both sides by 8ft of chain link fence. Over the fence to the south, up a steep and overgrown bank, is a 4-lane divided interstate highway compressed down to 2 lanes ATM, very busy, very congested. Over the fence to the north is the lake, with the distance between the fence and the lake ranging from 1 ft to maybe 15 ft. There is a gate right there in the lake-side fence, leading to a rock jetty that allows access to the drain that they are currently using to empty the lake. Most cars would fit between the fences on the trail, but never onto the jetty, and if a car were on the trail there, it would be both incredibly suspicious and illegal, as well as completely blocking the trail, which approaches blindly from around slight bends and uphill in both directions.
I don't know where people are thinking the dock comes in to play here. I never heard that the dogs keyed on the docks, nor that they even got to that side of the lake. The docks - as of now - are dismantled and stacked in the parking lot of the park area. I have pics that would show this, having trouble getting them uploaded.
Also, if the girls are in the lake, they somehow got WAY into the lake. Most of the lake along the shore is very shallow and muddy. I've seen pics of searchers walking almost across it in water that is only nipple deep in the middle. I will be shocked and surprised (altho, sadly, maybe a little relieved) if they are found in there when that lake empties.