Your planned 3’ x 4’ layout with multi ovals is rather small. You will be limited in the type of engines and rolling stock that will transverse the curved portion of the track.
The ability of the command station to power your layout will depend upon the engines and rolling stock. Engines with sound require a lot more current than those with just a motor and lights. Even the type of lighting in the engine has an minor effect on the total current demand on the DCC command system. As a last note on powering the rails older engines often require more current than the new ones.
As one who has built a small N scale layout, 30” x 60” for display purposes for the local model railroad club I can testify to the following:
1) The feeders that I used in the construction of the above layout were 22 awg sold wires, color coded for red as rail A and black as rail B. I found, in my case, solid wire to N scale rails easier than stranded. Beware of heat which can warp or damage rail ties. I suggest you use some sort of heat absorbing clamps near were the feeders are to be installed. You should use any color code you feel comfortable with. I used to purchase my feeder wire from Radio Shack. Now I purchase it online from eBay. There are many sources to choose from no matter where you obtain the feeder wire.
2) I ran 14 awg stranded wire for rail bus down the center of the length of the layout using the same color code as that of the rails (red to red and black to black. Some modelers prefer to solder the feeders to the rail buss while others indicate using a wire tap. I have used both over the years. If access to the wiring is easy then either work sell. If access to the wiring is difficult then you may want to use the wire tap.
3) Too many feeders does not hurt. Not enough feeds may cause problems. You can always add feeders if more are needed.
The above layout has been electrically problem free for over 6 years.
The NCE Power cab is a great starter DCC command system for the small layout and single operator. You may want to consider a more powerful DCC command system that allows for easy multiple operators. Note here that the Power Cab can be used in conjunction with the NCE Power Pro system.
Model Railroader 53 years
N scale model railroader 30 years