A lot of people including myself are starting to use this mod to set up mission control scenarios, which sometimes avoid using the in-game "mission planning" view. One of the major roadblocks is plotting an orbital transfer to another body like the Mun. Would it be possible to expose an API that queries the orbital status of the various celestial bodies? If so, I could write an orbital plot that aids in these transfer scenarios.

I would fork it and mod it myself, except without documentation it's a little over my head. Particularly, I can't figure out where the dataSources object is coming from or what its attribute tree looks like. Admittedly, modding KSP isn't my wheelhouse.

I will see what I can do.

I am going to work on the API tech required for serving body orbital information today.

Basic body orbital information is available in the 1.4.10.0 development build of Telemachus. You can download this from the OP of the Telemachus thread on the KSP forums, and view examples of the new calls in one of the posts.

I am guessing you will probably need more orbital information to make a complete display, so feel free to create a new GitHub issue with these in.