So far I'm unable to find a call / facility that I can programmatically obtain the current map maximum X and Z coordinates.
RustWiki only shows that its inside the WorldData object, but I shouldn't need to deserialize that beast to get current max coords...

Not sure if this is what you're looking for.. ?

float maxX = TerrainMeta.Size.x;
float maxZ = TerrainMeta.Size.z;
float maxY = TerrainMeta.Size.y;

int wrldSize = ConVar.Server.worldsize;​

zeeuss

Not sure if this is what you're looking for.. ?

float maxX = TerrainMeta.Size.x;
float maxZ = TerrainMeta.Size.z;
float maxY = TerrainMeta.Size.y;

int wrldSize = ConVar.Server.worldsize;​

That's it!  I'm still kind of new to the framework and to Rust plugins, so this helps. Thank you!
Also, besides the Rust Wiki that Facepunch has, uMod and just looking at what plugins exist, are there any other sites where one can get info on game-objects, functions and whatnot? 

recommendation is to use a decompiler like DnSpy, JustDecompile or ILSpy to view Assembly-CSharp.dll and other Dll in the Managed folder.

Lorenzo

recommendation is to use a decompiler like DnSpy, JustDecompile or ILSpy to view Assembly-CSharp.dll and other Dll in the Managed folder.

True! Sometimes I forget I have JetBrain's DotPeek and know how to scan assemblies :-) thanks for the reminder!