No rust on my Echo... of course I live in southern Texas.
The only way to fix that if the rust is that bad, is to cut out the old rocker panels and weld in new ones since it's a unit-body.
If you can catch it early enough you can wire brush the rust spots down to bare metal and treat it with a rust stop and repaint those areas. My old Celica rusted at the rear wheel-wells and that did the trick quite nicely.
Another cheap cheat if you've got lots of holes already in those areas is to do the above (treat and save the existing metal) and then use JB Weld or some other epoxy to epoxy on a new strip of metal - then paint it to match. It may not be pretty, but it might get it through inspection.
When did Maine start doing safety inspections, or is that only in the big cities? I used to live up in Presque Isle and we never had to worry about that.