Teardrops n Tiny Travel Trailers

I am trying to patch up the spots on my trim that I sanded through the epoxy and die, and wondering if there is a btter sander I could be using. My first attempt I used a mouse and or a electric randon orbit sander with either 220 or 320(don't remember as it was over a year ago). I am going to touch up the spots with die and put another layer or two of epoxy on,and just wondering what would be the best(budget minded)sander would be. The trim is about 2 inchs wide.

The trim in question is the dark trim around the perimeter.

Maybe a detail sander. I would start around 400 grit and finer. 320 is still pretty agressive.