I am looking at your mountains as we all work with the same isolating material... Do you have a "hot wire" foam cutter? I would strongly recommend that you buy one as it is one of the easiest tool to work with. Plus, there will be a LOT less mess created with all the small pieces of foam when they are cut with a knife...
Adding an helix is a complex project I haven't had the courage to get in to. I can already admire your motivation with your project!
the spiral tunnels portion willbe installed were the peninsula is now more or less, then benchwork will get some reworking to hold the loops of track for the tunnels, starting height off the floor is 48 inches and the upper track will be at around 60 to 62 inches off the floor when it comes around the room, ill most likely use styrofoam for the scenery again as its easy to work with, but im thinking ill use plywood for the track base then put cork roadbed on top just for more support, will see when i begin construction, hopefully get the demo part doen this weeka nd then start laying out the benchwork for the new layout next week
Whoever said you had to grow up never had a train set growing up