New Layout..DCS How to do?

I would definitely use blocks, and in fact would put toggle switches on each block to simplify operations.  Each siding should be a toggled block, for optimal operation. It is said that there should not be more than one hot (center rail) feed per block, and a layout this size definitely needs multiple feds for proper electrical distribution.

When you say grounds on both outside rails, I assume you mean both outside rails have ground feeds.  That is good.

Michael, your layout looks like you will have some fun running.  DCS also likes both outside rails tied to the Common.  If you visually stretch your main out 60+ feet with the dog bones on each end you would have something similar to the drawing below.  Mine is buss wired with the TIU Fixed 1 tied to the left end and TI Fixed 2 tied to the right end.  The dividing line is at about the center of the track based on length of track.

There's a lot more wiring information on my website.  Start here Buss Wiring Page

When you mean blocks for DCS, are you insulating the wired outer rail as well as the center power rail? Thanks, Michael

No.  Quite the opposite.  Aside from using insulated out rails for some functions such as signalling, breaks in the outer rails are to be avoided, since train wheels will jump it for long periods anyway.

Length of blocks depends, as one factor, on whether you plan to run conventional.