Leaking water on Passenger's side - HELP

Hey all,
In a bind here - borrowing my dad's old '91 GP. High mileage, but a good running 3.1L

Recently noticed a fairly steady water leak near the passenger's front tire coming from somewhere near the bottom of the overflow reservoir.
I have a 25 mi one-way commute so I've been able to top-off, drive, top-off, drive etc. No way I can get time to get under there and find the leak in the next few days.

Just thought I'd ask if anyone knows of a typical problem in that area, or the best way to go about finding it. Is there any trick to getting the reservior out?

It appears to be a long heater hose that runs from the heater core down a few inches toward the ground, turns toward the passenger's side for a foot or so, then down that side for another foot and ends around the underneath side of the coolant res.
Anyone changed one of these?
Is it relatively straightforward?

Just a follow up -
It WAS the long hose/pipe from the front PS engine to heater core.
Part # was Dorman 626-100.
I was told at Advance Auto that the part had just entered their system, and I could tell. It did not fit well. I had to force it into place underneat the overflow tank, and one attachment point didn't fit at all, but I felt that it was secured well enough that it would work as intended.

The old part was rusted completely through right where it ran below the overflow tank - the new part has cured the problem :)