What areas of the action to clean in an autopistol?

I'm far from an "expert" but you've hit on about what I do. I will clean the magazine from time to time also.

I use Hoppes number 9, and any good "gun oil." Break Free most often I suppose.

Clean everything. That way, you won't overlook commonly overlooked areas, such as the firing pin channel. I like BreakFree CLP.

All Of It. You don't need to do a detail strip or anything though. GunScrubber is great for hosing out the frame. Buy a set of those toothbrush looking brushes to scrub the slide with.

I use RemOil to lube my semi-autos. Couple drops on the rails, and anyplace I detect or see metal-metal contact.

There are lots of different ways people clean & lube their autos.

You're on a good start. Field strip and clean the barrel with a good solvent. Hoppe's is good, however I've started using RIG #44 and find I like it better. Use solvent on a patch to clean the breechface, feed ramp and down the magazine well. (Note: Foam swabs are good here too and better than cotton since they leave no fibers behind). I also clean the barrel bushing (if equipped), the frame's dust cover below the recoil spring and wipe down or soak the spring itself.

For lubrication I use Tetra grease on the rails (inside/outside) so there's a fine film. Also apply some to the bottom rear of the slide where it contacts and cocks the hammer. A film of oil around the inside of the bushing and a drop on the link pin (1911's). Don't forget to lightly oil the locking lugs and their slide recesses. Add a drop of oil or two along external extractors to ensure they can still pivot easily.

My main rule: If I see wear spots they get some kind of lubrication.

Depending on how much you shoot, about every 1500-2000 rounds, either remove the firing pin & spring to clean the FP channel or hose it down with a good degreaser to remove crud. Lubricate with about 2 drops of oil fore & aft and work the pin back and forth (excess can be removed with compressed air). On 1911's this is a good time to remove, inspect and oil the extractor.
Don't neglect cleaning and lubricating your magazines either!

That's all I can think of for routine maintenance at the moment.