Hi Zach,
First of all, I assume you placed the xPrint folder inside the xAct folder.
I do not understand what you mean when you say :"I first discovered that attempting to initiate it from init.m caused Mathematica to crash"
init.m is a configuration file that normal Mathematica users need not mess with.
xPrint has nothing to do with init.m, so I do not see what you were attempting to do with it.
The right way to load xPrint (like any other package) is to load it in a regular notebook, preferably in a fresh Mathematica session.
Just type Needs["xAct`xPrint`"]
xPrint will load many xAct packages for you, so you do not need to load xTensor, xCoba or xTerior.
The xPrint palette appears. The dropdown menus do not yet work at this point for the simple reason that they are context-sensitive, ie they show the tensors that are available in the selected manifold. If you did not first define and then - using the manifold menu - select a manifold, then the menus do not show you any tensor. That's why the big paste button says "No manifold".
So you must first define a manifold (with DefManifold command) and then select it using the manifold menu. At this point the tensors and derivatives menus start working.
In any case, you have certainly noticed a grey question mark icon on the right side of the palette. This is the standard Wolfram icon for the help menu that you should be familiar with. Click on it and select the xPrintDoc item on the dropdown menu.
xPrintDoc contains detailed xPrint documentation and step by step guidance.
Hope this helps