To make the building manageable, you only have to build the car. It will vanish and the roller coaster will be built centered on that spot. The coaster is HUGE, almost the size of Spectacle Island. However, it will build outside the borders of your settlement so you can literally put it anywhere.

Be aware that if you do this, it could clip into the surrounding environment. I claim no responsibility if you build this thing in Hangman's Alley and it crashes your game. I'm sure I will try at some point.

I wish I could say it's perfect, but it has a couple of minor issues.  The first time you use it, the passenger car gets stuck in the exit position. You can still ride the coaster, you just don't get the car. (see video) I actually prefer riding it this way, as the car can be janky-looking.

Also, you can activate it from anywhere on the model and it will magically teleport you to the launch position and start the ride. When the ride is over, you have to leave the coaster like any furniture (any movement key). If someone knows how to force the player out of furniture, leave a note in the comments, please!

That's about it. This is very much a BETA version. I will work to improve it as I get feedback and play with it more.

Included in this mod is a Ferris Wheel as well. It doesn't turn, and I'm not sure why.

Roller Coaster Normal/No Quest

300 Aluminum
125 Circuitry
500 Concrete
425 Copper
175 Gears
300 Screws
1000 Steel

Ferris Wheel Normal/No Quest

300 Concrete
150 Copper
225 Gears
150 Screws
450 Steel

Roller Coaster Super Cheap

30 Aluminum
15 Circuitry
45 Copper
15 Gears
100 Steel
40 Screws
50 Concrete

Ferris Wheel Super Cheap

15 Copper
25 Gears
50 Steel
15 Screws
30 Concrete