After lots of poking around I finally found what I needed here: The skinny on ScriptableObjects. This method lets me store all my precomputed data in an asset file that I can access through other scripts, which is exactly what I want.

You can't store properties just as class variables (I'm assuming you mistranscribed a static, since your code wouldn't even compile otherwise) and expect them to persist. They'll be trashed if that class is reloaded, and obviously will be lost on restart.

Simplest would be to store the calculated value in the actual scene object that ultimately needs it, not try to poke it elsewhere.

Certainly Kilometers. First you will need to create a class that extends ScriptableObject (make sure you have using UnityEngine at the top) for your stored variables. It should look something like this:

public class StoredData : ScriptableObject
{
    public float myStoredFloat;
}

Then, in your editor script have some method you call such as this one.

private void StoreData()
{
    //create an instance of your StoredData class
    StoredData storedData = (StoredData)ScriptableObject.CreateInstance("StoredData");
    //create an asset file at given path
    AssetDatabase.CreateAsset(storedData, "Assets/storeddata.asset");
    //this basically tells Unity that our scriptable object variable has changed and needs to be saved
    EditorUtility.SetDirty(storedData);
    //finally assign value to stored variable
    storedData.myStoredFloat = 1f;
}

What this will do is create an asset file that you can reference through other scripts and thus have access to your stored values. So somewhere in your MonoBehaviour have:

public StoredData storedData;

and simply drag the storeddata.asset file into the object field in the inspector.

That pretty much sums it up. If you have any further questions on how this works just let me know.