Icing and elevation do help to disperse swelling more quickly. The swelling will go away eventually, whether you ice and elevate, or not, but since swelling is one thing that prevents your knee from bending properly it does seem advantageous to get rid of it quickly, if you can. Ice is also a good pain reliever, too.
Ice to control pain and swelling
Elevation is the key to controlling pain and swelling
You need to ice for at least 45 minutes each time, or it's not effective. You can ice for longer and do no harm, as long as you have some material between the icing medium and your skin - to prevent frost bite. I know that some people use an electric throw to keep the rest of themselves warm while they're icing, particularity in the winter.
I did know about elevation, but I didn't know the benefits of icing when I had my first knee replacement. I recovered OK. However, I do think that icing made my subsequent recoveries a little easier.
I doubt that you'll see a huge difference if you start icing and elevation now, but every little bit counts - right?
As for how much you should be walking, give yourself a break.. You had both knees done at once, so you may progress more slowly. Just gradually increase the length of time you walk. I used to walk one block and back at first, then a block and a half, then two blocks - increasing about once a week, as long as I didn't feel any ill effects. Later, I took a timer with me, set it for 15 minutes, and turned back when the timer buzzed.
It doesn't matter how fast you progress, as long as you are making progress. Since complete recovery takes a full year, there's no need to rush at anything. Let your knees (and your stamina) take as long as they need to.
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