An update on the dilemma...
To access the fitting that was leaking, I had to remove the fridge and wooden panel beneath it. I also removed some elements of the interior cabinetry beneath the stove-top and sink to try and figure out the best viable option of fixing the problem. I learned a few things...
Lesson 1 - Replacing the water tank seems to be almost impossible. Anyone with a T-1700 that has to replace a water, I feel for you as just short of ripping out all of your cabinetry, I'm not sure how you would go about this...
Lesson 2 - The fittings that used on these water tanks are cheap and pathetic.
As the poster wrote above, it is a cheap plastic NPT fitting that is fitted against the tank; well, mine was split, as well as what looked like some kind of flange (green color). There were only two options to fix since the tank is near impossible to replace...
1. Cut a hole in the top of the tank to get behind the fitting. Remove it/Replace or somehow seal it up. Cut a new hole for a new fitting, and then patch the access hole that we would have cut from the top. We did not chose this route.
2. Use a combination of Teflon, pipe dope, DUMDUM tape caulk, an additional steel hose clamp and PET plastic welding to seal the crack.
Option 2 was a success. If I can get a picture, I will.
1999 Sunline Solaris T-2053
2007 Toyota 4Runner SR5 V8
1993 Sunline Saturn T-1700 (sold)