The club layout I was in was itself a learning curve layout from previous layouts and was designed right, unfortunately the club had to move, the layout torn out. PreDCC, 5 cabs. Anyways there were 2 towns the club decided were too close together, the engine should not be in one town and the caboose the other, so they decided to extend the run time, but however, most of that new line was to be hidden. I was the one who more or less engineered its construction and nopers, was not that fun, but was done carefull, and got finished. But I learned, I don't like hidden tracks. It was about 2 minutes of run time you don't see your train.
My current layout in construction is all modular multi-level, I can remove a section and take it to a bench and work on it closeup, turn it upside down to work on electrical instead of hovering under the layout. I won't have helixes to go between levels, it will be No-Lix all visible track. Or as much as possible, by design. I don't care if I violate some good principles, as long it gets the layout to work.
Good planning a must, but you know this hobby...8-D
Sometimes you get painted into a corner, but its a creative out to work out, and you find a solution.