Yes, your recovery will be better on AAS, but you have to remember that you are working harder and breaking down more tissue. You'll need added recovery, just to stay on your normal workout! Remember than muscles dont grow in the gym. They grow while we are resting. We need to get as much rest as we can. Get in the gym, do what you need to do, then get out, eat food and sleep as much as you can. If you find that you have a weaker muscle, it may or may not help to add in more volume, Ideally, you'd already know how your body responds to added volume by the time you are using AAS. 

If you really want to hit every body part 2 times, it can be done. The key would be to cut the volume down on each workout. So if you normally do 16 sets for a part, 1x wk, then hitting 8-10 sets, 2x wk is the direction I would go. There is a chance that doing this may improve your muscles, even if you add no additional volume, what so ever. Every time you train a muscle, you up regulate protein synthesis in that muscle. So 8 sets on monday and 8 sets on thursday, just might give you a better response to protein in that muscle. If you decide to try this, come back in 3 months and let us know how it goes for you. Just dont take on too much, too quickly. I'd pick a group that needs the most work and focus on that one first.