Well, I finally got the herculiner on this past weekend and it looks much better than I expected.
I ended up spending several days using naval jelly to get all the rust off the bed floor and then I sanded the whole thing with 80 grit before going back over it with 180 and a scotchbrite pad. The remaining paint in the bed was in pretty bad shape, not much shine left anywhere, so this was probably over kill but I was looking to get really good adhesion so...
I ended up wrapping the front rail, all the way to the space between the bed and the cab, with the herculiner. But only did to the top edge of the rails on the sides and the tailgate. (Going to put black rail caps and a tailgate protector on those.) After the second coat and a touch up session I ended up with less than a cup of herculiner left over. This was a long bed so I'd purchased the gallon kit and one extra quart.
A couple of notes...it was hot and humid so the only real issue I had with the application was that the product was drying a little too fast. Had to spend some extra time and attention to not get a noticeable line between the seams and corners where it was brushed on and the rolled sections. I've seen this stuff applied where there was a visible "line" around all the seams and it just screams roll on job so I didn't want that. I found that staggering the width of the cut in seams and being careful to only roll to them rather than over them did the trick. Cut in about 4" on the first coat, out from either side of the seam, and only 2" on the second coat. That took care of it.
The only other thing I learned it that you really need to remove your tape line pretty quickly after the second coat. If the product gets too dry it's tougher than the tape and the tape will want to tear. If it gets to that point you can simply apply a little more herculiner to the edge and it will re soften all the layers making it possible to pull the tape up cleanly.
All in all it was just like any paint job.....prep was 90% of the battle. The actually painting part was fairly easy but rather messy. Only time will tell how well it holds up. I'm really pleased with the results but now I have to go chisel the bedliner out from underneath my nails.