Bass Boat Conversion

I recently purchased a 1968 Sea King 14' V-Hull. It came with a roller-style trailer and 12" tires. The existing casting deck was not sealed and was rotting. It was also pretty low, minimizing the amount of storage I had. It will be used a "reservoir rig". That means it will be for small, electric-only lakes. I have a brand new Minn Kota Endura Max 55 and a Minn Kota Powerdrive V2 55. I have a size 29 Everstart MAX for the bow mount and a 27 for the transom. I want to redo the casting deck and repair the trailer so that it will last a long time.

Trailer Repair:

I need to replace a few of the rollers and one of the brackets that attaches the roller to the trailer. I may have to replace the winch and jack down the road, but for now, they will do just fine. I also want to seal the trailer and get rid of existing rust. Lastly, one of the plastic caps around the bearings of the trailer is missing. That won't be expensive, but I have to find the right one. Where can I buy new rollers? How can I make the rollers spin smoothly? Where can I buy a new bracket? Where can I buy the missing bearing cap? How can I remove existing rust? What is the best way to prevent future rust?

Boat Repair/Prep:

There are two bench seats in the boat. One is in the back and one is in the front. If I want to make hatches, which I do, I will need to remove them. That process will be difficult, but I will be able to do it without damaging the hull. Now that I have the hull completely stripped down, I want to seal the loose rivets. I have access to a welder and my friend knows how to rivet. I may want to coat the inside of the hull in a product that will keep leaks out and make it look nicer. I am thinking of truck bed liner. I also need to replace the transom. I is in bad shape, but there are several stripped screws, which is gonna make it really hard. I also need to weld the transom because it is cracked. Next, I need to begin the framing of the deck. 

Framing:

I have spent a lot of time researching what I want to do with the deck. I found one way that is particularly appealing. They happen to have the exact same boat too. They even made Youtube videos of the whole thing too! Here are the videos:

Tour: https://www.youtube.com/watch?v=mm0VrSjjlkM&t=71s

Part 1: https://www.youtube.com/watch?annotation_id=annotation_4258526983&feature=iv&src_vid=mm0VrSjjlkM&v=vZ_4u6s637g

Part 2: https://www.youtube.com/watch?v=8557c6AjL78

Part 3:https://www.youtube.com/watch?v=8557c6AjL78

I like how simple the build is. It would not be impossible for me to do something like that. I also have some ideas that I would like to add after the build. I would start the framing process by using 4 section of 2x4's horizontally in the front. There will be 2 2x4's stacked on top of each other. Lastly, there will be 2 4x4's underneath as support. 

then i add the wood and seal/carpet it.

Questions:

Where can I buy new rollers?

How can I make the rollers spin smoothly? 

Where can I buy a new bracket?

Where can I buy the missing bearing cap?

How can I remove existing rust? 

What is the best way to prevent future rust?

Does this support system seem good?

do i convert the boat on the trailer or on the ground?

What do you think of their conversion

anything else.