Eric -
The model years 1978 to 1979 marked a change in Dodge van body styles, mostly cosmetic. 1978 and earlier had separate front turn signals and side markers. With the 1979 model year, Dodge went to wrap-around combined turn signals and side markers. In 1978 and earlier models, people had to see the front of the vehicle to notice turn signals. In 1979 and later models, a turn signal could be easily seen from the side of the vehicle.
For now, I'm going to leave your 'backwoods shade-tree' front turn signals alone. Instead, focus on the easier restoration task -- the side door step wells.
1. Start by scrubbing the step wells with boiling hot water, dish soap, and trisodium phosphate (TSP). Very hot water and dish soap by themselves will work but the addition of TSP will make cleaner easier, faster, and more thorough. Use a medium stiff bristle brush and gloves to keep from 'cooking' your hands. (You want to work the dish soap/TSP solution in well, without scratching the paint.)
2. Follow with a thorough rinse using boiling hot clear water. (Or, at least very hot water ... hot enough to where you can't stand to dip your fingers in it.) You may want to use the thoroughly rinsed scrub brush. Regardless, you want to remove (rinse off) as much crud, dish soap, and TSP as possible. (The next step will handle the little bit of dish soap and TSP that might remain.)
At this point, you could use rust converter but the result would be evident when you're finished. If you choose rust converter, you need to remove all dish soap/TSP and dry it thoroughly. (I'd use a hair dryer or heat gun.) Follow the rust converter's directions carefully and use a degreaser if the directions say so.
However, based on your picture, I'd use a rust remover containing phosphoric acid. (Don't worry about the acid ... it'll be diluted and is the same thing that's in Coca Cola.)
3. Use a reddish brown Scotch Brite pad and rust remover. I use PPG DX579, diluted with clean water per instructions on the bottle. (If you can't find DX579, PM me available alternatives and I'll see if they're suitable for your purposes.) DX579 has two dilution ratios, a stronger concentration for rust removal and a weaker solution for metal prep prior to painting. (There's a third ratio on DX579 bottles for aluminum but I prefer to use other PPG products made specifically for aluminum.) Drench the rust and surrounding area with rust remover. (A spray bottle works best but you can swab or pour it on.) Scrub it thoroughly with the Scotch Brite pad, using a lot of physical effort, and wipe off the residue with a clean rag.
Initially, the rust remover will turn brown as it lifts and dissolves the rust. Repeat applying rust remover, scrubbing, and wiping clean until you don't see the rust remover turning brown. (You may still see some white in the rust remover, in the form of paint particles.) Extra applications and scrubbing is better than not enough. You should be left with bright shiny metal and dull paint.
You can rinse with clear water towards the end, to remove bits of rust and paint. However, the final application should be just wiped dry with a clean lint free rag and allowed to air dry. (This will prevent flash rust and help the paint adhere.)
4. Degrease, prime and paint. Grease and wax -- even minute quantities -- prevent the primer and paint from fully adhering to the substrate, so use a good degrease/wax remover. Priming is important because you essentially have bare metal.
You're going to have to be careful to color-match the paint. Blend (feather) the new paint into the old paint. (Primer needs to extend beyond the bare metal and paint needs to extend beyond the primer.)
Personally, I'd scuff up the old paint in the entire step well, clean, degrease, mask, and repaint the whole works.
