LFS Lapper is a program that uses the insim protocol to communicate with LFS.
Since all major communication with LFS is handled by Lapper, you only need to worry about creating buttons, store/retrieve values, etc to be done on certain events.
I have written a lot of scripts for Lapper (see Yisc's code release,
https://www.lfs.net/forum/thread/84505-Yisc%27s-code-release) and only ran into a few things which aren't doable with Lapper or aren't working as the are supposed to work.