Naval Yards

I remember seeing some on ebay a while back.  You can also check out all the online and local hobby shops, which should be an easy search.  That might get expensive though when you start getting distracted by the bright shiny kits and stuff.

Some Japapese companies used to make sets like that, Aoshima was one.  If you have a contest coming up you could check what some vendors might have, they still show up.

Another source might be some of the 3D printer people.

If scale is still on the table Takom did this ship/drydock combo in 1/700

https://www.themodellingnews.com/2022/02/in-boxed-1700th-scale-charlestown-navy.html

keavdog

If scale is still on the table Takom did this ship/drydock combo in 1/700

https://www.themodellingnews.com/2022/02/in-boxed-1700th-scale-charlestown-navy.html

... and old Loose Cannon (West) made some resin Structures based on Mare Island.  Alliance Models made PE  dockside structures including railroad track & stock

Naval yards wind up being sprawling affairs, even at 1/350 you could wind up needing the better part of a 4 x 8 sheet of plywood for a base.

A 48" x 96" sheet is only 1400' x 2800' to scale (1/4 by 1/2 mile, 426m x 853m).

For dockside cranes & accessories, you may have to scour the various 3d printing catalogs & web pages.

Sometimes for scenes like this that can have repetitive structures, i.e. dock-to-dock: a mirror at the back can be very useful.

Bill