I picked up RollerCoaster Tycoon 2 on GOG after learning about OpenRCT2. Pretty much it's an open source engine that allows the game to run on modern operating systems really easily. I've never played any RollerCoaster Tycoon before, but so far I've been having a great time with it!
If you’re looking for the modern version of this, Planet Coaster is a decent experience for those that enjoy RCT2. I’d recommend it if you can get it discounted. It’s better in a lot of ways when building coasters but doesn’t have the staying power that RCT2 has. Might give it a try though.