Frame inspection walk

Walk the rails. Do not assume they are straight because the truck sits level.

Look for:

Cracks at mounts, especially cab, bed, and spring hangers

Collision wrinkles and welded patches

Perforation in the bottom of the rails

Bent crossmembers

Suspect extra holes from past accessories

Photograph anything that is not factory-clean. Frame work is a path decision, not a later surprise.