Just for fun, here is a spiral polar plan that has reasonable grades.
About 120" from the exposed switch at the bottom to the outside loop cross over the hidden track in the mountain. If you do 4% (4" in 8') that gives you 6" in clearance. If you need more clearance, you can add another outside loop, which would be longer.
6" would be adequate for the Polar Express and figures on top.
This one is 100" by 62". O36 minimum, O63 maximum. Two O36 turnouts.
The rest of the grade can be easier if you like. If you stay with 4%, that adds another 16" of height, for a total of 22" to the top plateau.
This happens to be Atlas-O, which fits on a single width of Woodland Scenics inclines. Which are not that expensive, if you add up the inclines and risers, maybe $200? Would have to work it out for a precise figure. Then fill in the spaces with whatever you prefer.
Put a lift-out Christmas town inside the top plateau loop. And a taller mountain peak outside of it, perhaps another 8", to top out at 30".
