My concern would be the carpet will hold moisture if it gets wet (and IMHO, it will eventually). Many of us have had to deal with leaky rear door weatherstripping. So wet carpet is a possible significant concern. And if it wet and gets moldy, you will be pulling up the wood floor to get rid or it.
It really is not that hard to remove the carpet, but the padding might be a bit of trouble if it has stuck down to the floor.
When my carpet got wet, I was able to just roll it up toward the front seats, put a few large blocks of wood under it, lay it back out more or less flat, but off the floor ( on the wood blocks). I set a fan in there for a few days and it dried out just fine.
The carpet will provide some sound deadening, so that might be a consideration if you do remove it, but I think some rigid foam would work pretty well in it's place, or even put in sound deadening mats ( like used in door panels and trimmed to fit ) under the plywood.
Just my $.03 worth.
Rod

 

Not to mention that the carpet could have been wet in the past and the floor below could already have rust on it that you need to treat before it gets worse.

Much better to get it up, clean and treat then install insulation, underlayment and the flooring.

 

Thank you both for your reply. Makes sense. I'll just take it an hour at a time when I have the time and do it slowly and correctly.

 

Are you planning on SAVING the carpet, for some reason? If not, then why not just grab a utility knife and blades and remove it the FAST way?
Just a thought....
-M!ke-

 

Not to mention that the carpet could have been wet in the past and the floor below could already have rust on it that you need to treat before it gets worse.

Much better to get it up, clean and treat then install insulation, underlayment and the flooring.

^^This.^^
I ran into that years ago, as I'd find damp carpet while crawling around inside on my knees. I pulled the carpet out, then the factory sound deadener which was still soaked and holding water. I hung the carpet up on a clothes line to dry out, and buzzed the floor before putting some primer and paint on it to seal it off. I've since just tossed the carpet in, but it still needs the seals replaced (they're 30+ years old now).