Not that hard
I did it a couple of years ago. Use a razor knife to cut the brown calk. Angle inwood a little away from the fiberglass. Use a wide chisel to start prying the sole up at the corner of the bigger section. Work very slowly to give the calk time to stretch and release. Once you have a corner lifted high enough to get a pry bar in, start using that to slowly lift the sole from underneath. Work slowly toward the small section by the aft birth entry because that is the place that is most apt to snap. A regular razor scraper will remove all the calk you need from the underneath of the floor and the fiberglass. To get the brown calk from the fiberglass, I drew the razor knife back over the remaining calk. Not toward it as if you were to cut. That solvent mentioned in the previous post sounds like a good final cleanup, but I used a nylon scrubber and a little elbow grease. I put the floor back with a silicon calk because that is what it looked like it has been put down with. I suspect that you don't want anything as permanent as 5200 or there might be a chance that you could never get it up again without breaking it. The colored calks for the edge are available from WM. Follow the instructions and use masking tape as recommended.All that said, the seal on my floor was very tight. Are you sure the spill got underneath the floor???