RCTgo

1) Go to "Roller Coaster Tycoon (...)" in your documents.

2) Scroll down to the Text Document labeled "Options."

3) Press Enter, then paste: 
"AttractionSceneryAllowTerrainIntersect 1
AttractionSceneryAllowSceneryIntersect 1
TrackAllowSameTrackIntersect 1" (without quotation marks, after your screen dimensions for the game)
4) Click File.

5) Click Save.

6) Then exit the text document.

Hope this helps!

Here's a video tutorial too: 
https://www.youtube.com/watch?v=48U0dERhsfQ