Finished the carpet install today. The fussiest part was trimming the carpet around the shifter so that the rubber boot is under the carpet (to seal moisture away from the carpet and padding) but with the carpet edge still covered by the trim plate. I'm pleased with the result.
I've started working on the seat now, have the replacement side support spring in place, and have just a couple little tweaks left to secure it. Then I'll strip the original covers off and assess the condition of the foam.