What's a good way to secure bushings in a 3D printed part?
If the outside of the bushing will bond well to the epoxy, your method is simple and likely to be effective.

You could use the same method used for threaded inserts by roughing the exterior of the bushing, heating it and forcing it into a correctly sized hole printed in the model.

The threaded inserts are knurled or otherwise textured to provide stronger bond with the melted plastic. Knurling your bushing is more complex than a good epoxy bond.

I've discovered a product called "castable bushings" which would appear to meet the above requirements for heated inserts:



The product listing indicates that these are used for drilling jigs.

It might be less messy but more expensive to purchase and use these as opposed to epoxy and a bit of sanding.