Title says it all :-) Roller coaster style! And you can run another track underneath.
Print the bridge on its side. It has quite a steep overhang, but it came out fine without using support. Print the insert upside down. Glue into place with a dab of CA glue. You may have to sand the insert a bit so it doesn't damage your cardboard base plate.
The ball needs quite a bit of speed, so a magnetic cannon or a drop from a 3.5 unit high pillar is needed.
Here's a video with most of the elements in my library. And... a preview of the lapse timer I am about to release. The lapse timer has custom electronics that I will be making in small batches. If you are interested in the lapse timer drop me a message. If there's enough interest, I could consider ordering larger batches of circuit boards and components.