Great looking track work and layout so far. I kind of like switching puzzles too if I have the room. Looks like you did a good job planning for your grade, somethng a lot of modelers don't. The only thing that makes me cringe is that section of grade that curves right to the edge of the layout. That's prime territory of a derailment and you best engine in pieces on the floor. I'd think about some kind of above grade retaining wall or even decorative fencing to keep your train on the tracks when the inevitable derailment occurs.