Waterproofing the bed checklist

So I'm getting my bed sealed prior to getting topper installed and just want to make sure I have everything I need to do the job. Here are some sealing material I've picked up from home depot.
https://www.homedepot.com/p/Fabral-1-4-in-x-40-ft-Butyl-Rubber-Sealant-Tape-40BT/207149821
https://www.homedepot.com/p/1-2-in-x-1-2-in-x-20-ft-Expandable-Foam-Weatherstrip-03110/313961254
https://www.homedepot.com/p/M-D-Bui...le-Caulking-Cord-Weatherstrip-71548/100353483
https://www.homedepot.com/p/DAP-Ultra-Clear-5-oz-All-Purpose-Waterproof-Sealant-18387/306641586

Areas to seal up

1. Front top corners of the bed (butyl tape)
2. under the plastic bed rail caps(planning to use that expanding foam tape to see how well it works)
3. tailgate with
   $29 ESI Ultimate Tailgate Seal with Taper Seal 10ft for use with Truck Caps and Tonneau Covers
   https://www.amazon.com/gp/product/B00IPQWXZQ/ref=crt_ewc_title_srh_3?ie=UTF8&smid=A26GQRWSJVLGWV
4. the cubby boxes (haven't figured out what I'm going to do yet)
5. caulk around the power outlet

Let me know if I'm missing something in terms of areas to seal or material.

 

Regarding the front top corners, I would recommend the OEM plugs plus silicone sealant. A little trimming of the plastic bed caps is necessary.

As to the plastic bed caps themselves, don't use foam tape. That will flatten and disintegrate over time. Use silicone sealant, and apply it inboard of the holes in the sheet metal.

The cubby boxes can wait until after the topper is installed. I would recommend Mike Williams' 3D printed "Cubby Caps."

Not necessary to caulk the power outlet. I haven't had any leakage there.

 

I have no idea what oem plugs you are referring to. Can you explain or link? I assumed butyl tape should do the job just fine for the corners since that seems like what most people use. Can you also go into more detail on trimming the bed caps?

 

The plugs are Toyota part nos. 6254104010 and 6254204010. They run about $32 each. These are normally installed with factory tonneau covers.

The ends of the bed caps have to be trimmed for the plugs to fit. A small, irregularly shaped area about 1" square has to be removed. The whole process has been discussed in detail elsewhere on this forum.

 

Thank you for your help. Looks like you've helped many others prior. I've found the posts you were referring to. I'll link them here to help others.
The plugs
https://www.tacomaworld.com/threads/rubber-plugs-for-gaps-in-bed-rail-available-now.420884/
Bed boxes
https://www.tacomaworld.com/threads/diy-how-to-weatherproofing-the-bed-cubbies.452381/#post-13287032