The P&W-RR will be using traditional block control as I haven't got the DCC bug as of yet (and using DCC would probably represent a significant challenge for Z-scale even if I did!:o) Anyway, most block designs can be converted into DCC without much effort if I ever do choose to take on the challenge.
The layout drawing below has been annotated with my initial block plan. The red marks represent the isolation points in the track with both rails being gapped. Given this approach, the mainlines will go through 6-7 blocks depending on which path is taken through the yard shelf. A number of storage, service and industry tracks have independent blocks as well. In reviewing this plan, please remember that Märklin track switches are fully live through both routes so isolation of branch lines need to be added with additional gaps (as shown). Built-in power routing is a feature of the Kato N-scale switches that I have and really makes blocking the layout much easier, too bad this isn't available with the Märklin track switches! BTW, the gap locations shown are approximate and are likely to shift slightly to adjust for clearances at track intersections.
You probably noticed the reversing loop ... my plan includes the use of the Märklin reversing kit shown as a series of three red marks in the hidden reversing track. The reverse kit uses a sequential series of three specially wired tracks that only works in one direction, the operation being that the train automatically stops over the second track in the kit to allow the operator to reverse the track polarity before finally proceeding through the loop. As noted on the drawing, you can see the direction that I plan to use. I'm setting it up so that reversing a train will normally occur by an operator viewing everything from the South side of the layout and this direction provides appropriate viewing to make sure trains clear the West side switch before proceeding forward in the case of backing a train through the loop. Also note that the whole reversing loop is contained in a single block as I don't intend on storing trains in this hidden section and the reversing kit assures that no loop short will occur.
I haven't yet decided on what toggle or slide switches I will be using for the block control but I have decided on using lever operated passing contact switches from Peco for the track switch controls. The Peco switches operate much the same as the Märklin switch controls but take up less space and provides better visual indication of position ... besides I've liked the way they appear and operate ever since I first played with one many years ago (although this is the first time that I'll actually use them in an operating layout).
At a future time I'll add some discussion of other electrical topics including wiring, power packs, trip switches for feature controls, etc.