I did try your track late last night, it ran ok, but took long to load. Now I took the liberty to peak inside one of the kn5 files... and it shows the issues of RTB build tracks.
You've got 359 texture files, most of which are duplicates. Like STONE_WALL.dds to STONE_WALL15.dds are all the same identical texture, the same is true for every same named texture with a number behind it, you are trowing away A LOT of memory space and performance here (I also expect your upload from RD to be deleted, as the site does not allow split uploads afaik).
the marked files (~92 files, 119 MB) are unique, the rest are duplicates
I assume RTB did the same with materials meaning you have tons of duplicate materials all around the track, which may not be that bad for performance but make it harder for you to maintain the track if every house needs to be modified on its own.
There is also the common "xpack" issue of 1024x1024 DXT5 textures of single colours
edit: I know this sounds negative but I really like your track and the idea

There are too few well done hillclimb tracks around for AC