Ah, the joys of non coders mucking about. I'd suggest getting a git/mercurial environment set up for them. Tell them to save everything in a format that the repo can handle. With tortoisegit or tortoisehg, they don't need to know how the repo works. They just check if they have an exclamation point in their project directory, right click the offending file, and click commit. Type up a synopsis of changes(they're writers, right?) and you are done!

An extra step in the work flow for them, but nothing about merging/branching/cool stuff. The pre built environment is already set up to be in the writers branch, so they don't see code. Have a script auto sync them every day. Later, after they are used to committing, you can show them extra features. The ability to see what changed when is so useful that they won't be able to do without it, once you sneak it into their workflow.