I'm moving a site about 400 articles deep onto a clean CMS and the migration is the part scaring me. three writers over four years, so the fields are all over the place, inconsistent bios, a chunk of pillar pages orphaned. traffic's fine, it's just unmaintainable. What i'm stuck on is the actual move. how do you standardise the fields and get 400 old posts into a clean structure without hand entering every one, and without a rebuild quietly rewriting pages you didn't touch? i'm not a dev so a script isn't on the table.

How have people handled a migration this size?