Deck sanding/preparation

Attached are pics of our front and back decks.

The back deck has recently been extended, which is why the boards in the foreground (A) are new. They are Kwila and don't have anything on them yet. I'm not sure how old the original boards are, but it looks like once upon a time they had some paint on them which is mostly worn off. I ran the orbital sander over a few of them (B) to see how they would come up. The boards in the background (C) are original.

The front deck looks like it hasn't had anything done to it for a long time. The timber is some sort of hardwood, and is in reasonable condition. There are lot of nails in it, some of which I will have trouble punching because they are not over joists (go figure). Also the boards vary in height a bit.

I want to clean up both front and back decks, and put some Sikkens Cetol HLS on them. I was thinking maybe a light sand of both decks with a belt sander, then some Intergrain Reviva by way of preparation. Alternatively I could hire a floor sander and then I may not need to use the Reviva.

What does everyone think?

I've heard that you can get some pretty amazing results using a high pressure washer and some of the deck cleaning chems that you can buy at any hardware store. Not that I've done it myself...

Otherwise I'd go with the floor sander - just to save yourself too many hours on your knees with the sander...

Trav