I figured it out. Slightly harder than I thought it would be, but only slightly. Working fine so far.
For those who want to know. You don't really need to know how to write scripts, just how to read them.
Place a new Mojave Express Box from the object window then name it and make it a persistant reference. YOU MUST DO THIS NOW OR YOUR SCRIPTS WON'T SAVE. You need to create a reference and give it a name before you can write it into a script. I know it's a newb thing but it's easy to overlook.
From the Object Window, select vMojaveExpressFirstMessage. Copy the conditions for one of the other boxes listed and in the first condition select a new reference (the one you just cplaced and named in the last step). In the second condition, change the name to the new box name. Save it.
From the Object window again, select vMojaveExpressShippingMessage and do the same steps as for the last one. These 2 steps add your new box to the menus and add it to the overall quest to discover the Mojave Express Boxes. The next few steps add it to the Mojave Express "system" and make it function.
From the Script editor open vMojaveExpressBoxScript and look for any reference to the other boxes and copy and paste one of the others mentioned then correct the name. Any specific reference could be up to 3 lines of code but if you can script, you can figure it out.
Do the same thing for any other scripts with "vMojaveExpress" in the name, 3 of them I think.
There you go. You can now add a Mojave Express Box any where you want.