Harking back to the difficulty you have of getting enough room between that crossover in the NNWest and the red track crossing the green in the NNEast for a reasonable grade, how about shifting that crossover to just below the RH entry to the main yard where both red and blue are on the same level. That way you can then start that NW grade back closer (about 6" north) of the bridge over the SW lake. The red track will by necessity be a high line all the way past the branch tracks (SE) and over the green before it can start it's down grade towards the main yard again. I can't see anywhere that you have provided a return crossover so that the train that has come off the red can return to the red i.e. without a lot of manouvering. It can't get off the green easily. How about, at that red and blue track's proximity, either a double crossover, or opposite direction crossovers one after the other at that spot.
By eliminating the crossover in the NNW, the height you should be able to gain, with the longer, lesser grade, may enable you , if you wish, to raise the green track instead of dipping it under the red.