Thank you to all who have responded. I truly appreciate it
My 48 backhoe is set up to have just two hoses connected to the tractor but I notice in the Installation Instructions there is a mention of three hoses.
1. Backhoe Sump Return Hose
2. Tractor Pressure Hose
3. Backhoe Pressure Return Hose.
On my set-up there is no Number 3.
In attempting to bring myself up to speed, I found a page that explains some things and has pictures (pictures are great) but I do not have the foundation to understand some of the presented information. The page is at:
Selective control valves (SCVs)
For example, this may not be what I need to understand for my task of connecting my backhoe, but I have no idea what a rockshaft valve is - as mentioned in:
5005 Series tractors can be equipped with as many as four economical and versatile spool-type selective controls valves. Up to two rear and two mid SCVs can be factory or field installed. For additional versatility, a power beyond kit can be adapted to the SCV and rockshaft valve to supply live hydraulic power to hydraulic motors and implements.
My tractor has a single selective control lever to the right side of the operator. However, the statement about "positions" displays my lack of knowledge - what is a "detented float position?" Does float position have anything to do with my being able to use those couplings on my backhoe? Or, is my belief correct that "float" has to do with plow/blade depth control and not an open live hydraulic power flow? The paragraph states:
Single and dual selective control valves are available. Each valve features extend, retract, neutral and float positions. The single SCV features a detented float position. The dual SCV features a detented float position on the #1 valve and regenerative position on the #2 valve.
I have re-checked and can now confirm that there are 3 hoses on my backhoe. The 3 couplers on those hoses are:
Pioneer Female Coupler 4050-15 3/4-16 ORB
Pioneer Male Hydraulic Coupler 8010-15 3/4-16 ORB
Faster HNV 38 12 SAE EFJ 06NO with "Made in Italy" (I am guessing this is metric as the male Pioneer coupler will not even fit into it.)
In attempting to understand how these 3 hoses connect and function? I want to Thank
Quebecguy for his help.
I've searched for pictures of a Power Beyond installed - the pictures I have found seem to indicate that the Power Beyond when it is not connected to the backhoe is in a loop back into the hydraulic system (can someone confirm if I am right):
I found a different picture that seems to confirm:

And then I found an explanation and picture
The PB (orange) is plumbed into the DSCV block which is located behind the joystick. The lines run to the top back where a bracket mounts above the 3 point. And a return line (teal) runs to the side of the hydraulic fluid fill. The dark blue is the 3rd function.
Since the Power Beyond Kit is not available - I wonder if the individual parts might be? Comments?
Can anyone make a recommendation of finding the kit RE73308 or sourcing the individual parts?
Lastly, in the interest of a solution, I am wondering if it is possible to purchase longer hydraulic hose extensions to go from the backhoe to the mid-mount hydraulic connections that are used by the front-end loader? However, I am uncertain about where to connect that 3rd hose - the mid-mount shows 2 pair of couplings (I assume 1 pair for boom up and down and the other pair for bucket "open and close." But a connection for 3rd hose remains a mystery.)