Wow Boss, you've been making progress. Looks really good, and this car is certainly no rust bucket. Metal looks very solid. Others may have better suggestions, like Por15 or similar, but I like old fashioned Ospho to treat rusted areas. It is cheap, and flows into nooks and crannys because of it's waterlike consistency. A quart is something like $ 7.00 in hardware stores.
Here is a little write up on Ospho:


The active ingredient is phosphoric acid.

Ospho is greenish liquid with the consistency of water. Brush or spray it on rust after just knocking off the loose scales and it pretty much stops rust dead. It also leaves no residue. There is a product called "Neutra-rust". It may have ospho as the active ingredient but its in a milk-like base that changes from beige to blue/green when applied. It then leaves a sand-able coating.


Ospho stops rust, prepares rusted surfaces for painting. Ospho is a primer-not a paint. You do not have to remove tight rust. Merely remove loose paint and rust scale, dirt, oil, grease and other accumulation with a wire brush. Apply a coat of Ospho-let it dry overnight, then apply the paint. When applied to rusted surfaces, Ospho causes iron oxide to chemically change to iron phosphate - an inert, hard substance that turns the metal black. One gallon covers 600 square feet.

part# description
1280-011 ospho 1-qt
1280-01 ospho 1-gal


Like I said, there are many other products, but for the money, I like this one a lot.

Don