Accessing 2012 Sport shower drain from below/pan

[GaryRI]

Anyone access/fix a leaking shower drain by dropping the exterior pan?

My Sport has the bathroom across the back end and only was to access drain is from beloe.

I am a week into using my Sport that was been in unheated storage in San Antonio (remember last winter was super cold down here!!!) for almost a year. I did have the Sport winterized.

I noticed a small drip on to the ground under the shower, near the stabilization jack, from between overlapping floor pan sheets. I called the shop in RI that added a rear bumper for me a couple years ago, and the shop owner recommended poring water with food coloring in the shower drain. I did this last night and BINGO the dripping water is the same color as food coloring.

I looked underneath the closet and there is no dampness there.

Seems obvious the Sport wasn't winterized correctly but I have no interest in fighting with that shop.

Youtube has a clip showing full pan removal on a really old Airstream. Doesn't seem like a big deal.

Is this something I can fix myself?

Thoughts?