That's about it.
Personally, I'd use something like Nitromors(SP?) (test a small area first!!)
. Around welds and tricky places work it in with some wire wool, you'll be amazed how well the stuff works. The paint is only a thin layer 'cos it's sprayed on, this stuff will take off years of paint from exterior doors so your bike frame ain't going to be a problem.
Once the paint is off, check the condition of the frame. I've never done the caustic soda thing, so don't know really how that's going to work, you'll just have to experiment I guess.
Then concentrate on any deep scratches and sand / polish them out before giving the whole frame a good going over with fine wire wool and brasso for example.
Finally finish it off with a good metal polish and a cloth. It's going to be a lot of work, and you may just decide to leave it nude once you've put all the work in.
That's the tester really, if it looks like a polished alloy frame once you've finished, then it's good enough to anodise... That's the kind of finish you're after.
If that's not put you off, then good luck and I can't wait to see the results.
WANTED: RS Mag 21 with 1/18" unthreaded steerer | USE Stealth forks or spare parts