It does not seem that park access for the public is a priority in the Phasing of the Reimagine project. The outstanding question is how might County Parks configure the various project phases to insure the maximum park availability to the public.
On the quick review, it seems that the park could easily be open to picnic, volleyball, horseshoes, and walking, and enjoying the woodland nature during renovation work on the sports area of the park.
Similar, it makes sense to have as many picnic areas as possible available during construction in other areas of the park.
If you agree, please see the Action page for ways to let County know. You can also use the Contact webpage to leave a comment and these will be routed to others as appropriate.