Applying a 'master' set of policies to a number of computers in a non-AD environment

While there is a way to do this, I'm hesitant to describe how to do it. It's 100% unsupported from Microsoft, so to give you "unsupported" advice means we're entering a slippery slope together. However, one way of addressing a part of the problem is by security templates. Security templates are a "portable security knowledge" which you can create on one workstation then, if you want, walk around to the rest of your workstations and also apply. There is a good Microsoft article here about the "built in" security templates and also how to create your own and apply them as you see fit.