."...anyone have any methods/ideas on how to get rid of, fill in, or smooth out larger gouges or dents in the anodized coating? ..."
If you have dents or scratches that need to be filled, an issue to be cautious with is the bond to the aluminium. It oxidises so quick.. You can scratch it with fine sandpaper or scotchbrite to get a key and clean it with solvent then apply the filler (glue mix) quickly. Sometimes to get a bond to aluminum I have abraded the surface wet, with epoxy as the wet medium. No oxide is possible. A bit neanderthal, but it works.
Once a suitably hard and tough filler has been added to a low spot or gouge (epoxy resin with glue filler?), the problem then is how to dress that back to shape without adding a large area of scratches with the sand paper around the actual repair. Familiarity and skill can make that easy. Otherwise, there are some tricks. For straight surfaces, developed surfaces, as in any surface that you can create or simmulate with a curved piece of cardboard. Sanding blocks with the paper stuck to the block. Double sided tapes on aluminium box section is good. Wood blocks are ok, I suppose (nah). If you are not familiar or are out of practice, wrap some masking tape around the ends of the block, and you will then only be abrading the high spot.
Use glued sanding blocks to shape stuff in a controlled way, then softer blocks with some cushioning with finer paper to smooth and blend stuff.
A marine laminating epoxy like West with some glue filler might be ok. Sorry George, bondo is crap for this sort of thing, unless one is unfamiliar with the sand papering, in which case the softness (relative to the aluminum) will help keep one out of trouble.