Blasting will always get to the parts a disc cannot reach,but I'm assuming your truck is a Texas truck,so the rust shouldn't be too horrendous?
I'm using discs on mine simply because there's no-one locally I can trust(or afford) to blast mine.
I've stripped mine with discs and hand sanding and am using POR Metal Ready to stabilise the remaining bare metal.
I'm top coating with
POR-15 paint and have been really pleased with the results.JMO