You should check out the 2.8L forum. There is a ton of duraspark info there. Also check out the tech library as it has diagrams.
You can get everything from the junkyard or from various vendors (eBay, NAPA, Autozone, etc). At a minimum you need a non-TFI distributor, control module, non-feedback computer, and the requisite connectors.
I believe the resistor wire comes in to play with the canister-style non-TFI coil. If I recall correctly there is 12V to the distributor when starting which drops down to 9-10V during operation. I assume that is to increase longevity as I've seen some folks on here have found the coils to be sizzling hot if they didn't drop the voltage. I've also ready that the TFI coil is OK with 12V so there may be no need to add a resistor wire if you already have the TFI coil.
I was curious if you could make the TFI distributor work without the computer. The short answer is yes, but you will not have any timing advance. This is OK if it's just a farm truck or offroad beast but not so good for highway mileage.
FYI, I've found the distributors on average are $65 with a $15 core, but come bare, so you'll need a cap ($10ish), collar / adapter ($10ish), rotor ($3ish). Coil connectors are $6ish (won't need if you keep the TFI coil), control modules are $20-$70, and wiring you can reuse from your harness.