Thanks again JA Savage!
When I take the next decisive stab at it I'll look into the bottom of that heater box again because I can just see the two copper pipes sticking down from that heater coil. I'm hoping to connect them there once I remove the rest of the piping that was running rearward to the heater. Hopefully I'll be able to connect them there from "T" to "T" where they exit the bottom of the heater.
There's not a lot of room to work in there but it would sure make for a clean and tidy connection, one that is fully inside the heater box and safely out of my way as I'm planning on couch seating immediately behind the driver's seat that will house the electronics.
And roger that on the coolant!
Wish me luck!