I want to copy and paste a custom game template I already made to turn it into a single player level. Is there anyway to do this without having to do everything all over again?

Yep. when you make a custom single player game choose to use a template you've already created and filter it by "my saved multiplayer templates".

cool right?

Edited 1/30/2017 03:18:51

Speck, he is talking about making it into a SP Level, not a local SP game.

No, there is no way to do that at the current time. You have to reenter all the details when you are making a level, even though you have a templateID :(