I agree with saltfishermans reply about being careful about losing items that could be picked off while traveling could come flying out on the road......and never store your PA-17 with all of your treasures in an open area......inside your garage is the safest storage.
For the record I own a 2013 PA-14.
1. Since I have a Humminbird 768 fish finder, I did not have any cable connector issues when mounting through the pre-drilled holes and the Hobie fittings.
2. I leave my seat in when traveling, but do have a 1/8" nylon cord safety leash connected to the seat frame just in case.
3. Fish finder......I used a Ram ball and 6" extension....I place/secure a heavy duty Glad plastic bag over the whole unit and fold it down parallel to the deck....tighten the wing nuts and it travels w/o any issues. Photo shows the elevated position and is easy to rotated "down for trailering".
3. Rods.....I carry my rods with reels in my car.
4. Non-submersible tail lights....My Hobie Trailex trailer came with "submersible tail lights", but from past experience, they will still cause problems. I relocated the lights on a 2" x 2" wood post and 1/16" thick, "L" angle slotted, zinc plated steel support as shown the the photo...I used a 18", 4 wire trailer pig tail, to make the connection and U-bolts with wing nuts for easy on/off.
5. Winch....Go for it as you won't be disappointed when loading the kayak on the trailer....especially on a steep, angled ramp. I used a 600# capacity winch mounted on the post in the photo.
