Project your railroad's operations within the city and/or countryside scenery, and then plan your benchwork to augment what you need to do for those specific railroad operations.
N Scale CR&T is multi-level with dogbone-style track planning on each level.
The U-Shaped layout's outer dimensions are 9' along the back wall (including an extra 1'x5' notchback section used by the helix) and 6' on each side. The helix will have at least 2 tracks (for coming & going).
CR&T combines (4) types of benchwork: L-Girder, cookie-cutter, box/grid, and shelf brackets.
Lower level is the layout benchwork base...
Combination of L-Girder benchwork, and two neighborhood locations with cookie-cutter (and box/grid).
Upper level benchwork -- to eliminate 'lower level view-blocking' vertical wooden supports...
Shelf-brackets with box/grid benchwork construction on either side of the top-summit helix tunnel portals, With shelf brackets, you can construct an 'L-Girder equivalent' for height, rivers, etc., by using the adjustment built into the shelf bracket supports.
The helix actually serves as a benchwork anchor to either side of the helix regardless of upper level or lower level.
Plan in terms of what your railroad will be doing...
Lower Level -- a city & industrial concentration focused on the CR&T traction system.
Upper Level -- a 2-track Pennsy mainline to also make a helix run down to the lower level to surround the CR&T with freight & passenger interchanges.
Potential Staging Level -- stlll working on this to shoot out of the helix -- more than likely box/grid on shelf brackets.
ASK: What is it you are to accomplish with operations? Adapt benchwork accordingly, and wIth some patience, by taking your good 'ole time planning, the answers do come.