If you want to sand the deck to rid the deck surface of the paint, that is one reason, BUT to sand a PT wood deck to make it smooth is a pretty tall order to ask of that wood.
Once PT wood has dried, and five years its dried, its a very hard wood. I have been told that the chemicals solidify and encase the wood. The wood will still contort and twist and cup, but it does become very hard.
Sanding, as I have done many times, yields a semi smooth surface, but comes back to its rough charactericts.
I found that a drum sander with coarse paper does do the job fast, but it does gum up quickly and with a 200sqft deck, you will maybe need 15 to 20 replacement papers.
Then you must set the nails or screws down deeper. The paper either gums up quickly or tears on the splinters or nail heads. One small splinter will ruin one sand sheet.
Have you tried pressure washing the deck to rid the paint? A 3500 psi sprayer with a fan tip will remove allot of paint and allot of the debris in the wood. You might try this before you sand and if you sand after this spraying be sure and wait for the wood to completely dry out.
You should be able to rent a 13 HP Honda engine 3500 psi rig with spray tips for about $80 a day. And you can surely do that size deck in one day.
I have started with one 2x6 and worked all down that board and then to the next one. This might take care of your paint problem
The smoothing out of PT wood just might not be possible.
Please understand this I have done this for many people and it just does not come out like I would want and some customers were unhappy when they thought the wood would come out nice and smooth like your coffee table surface. Just will not happen.