I prefer to till it in. fall is a perfect time, and 2-6 inches should be composted by next spring. In TN you probably should add some lime.

It's more work, but I'd throw it in the compost bin until next year and work it (It'll need air to break down) to make as much compost as possible by next spring. The compost could be worked into the soil and any leftover grass and leaves could be used as mulch. The mulch would be beneficial for nutrients as it breaks down, but would serve double-duty as a good mulch in the mean time.

I agree with tntom. I would only add that lime would be a potential important amendment if you are talking about spreading it over a vegetable garden to bring the pH to more neutral.

I also agree with tntom. Have done it both ways and when your age moves up to 81 I like to see less work with good results.

My general rule of thumb is ...Til into in the garden and compost it for flower beds (unless you have a tiny garden).
You'd have to be Cpt. Compost to have enough compost for your garden. I love to have a dozen wheelbarrow loads of compost every year for the flower beds. My 4x4x4 compost bin yields 10-12 wheelbarrow loads each year and that stuff is so rich it's BLACK.
Norm go find a couple of truckloads of horse biscuits to till in there too. Wear gloves or Barb won't let you back in the house.

How long does it take for a large, way over my head pile of leaves to break down? Ideally I would mulch them but I have no way to handle that many leaves.

Ktowngardener, maybe a few months depending on how they are handled (shredding them makes things go much faster), temperatures, etc. Adding Nitrogen (grass clippings, table scraps, chicken manure, etc) will speed things up greatly.

Where do you get those biscuits? We we were a more agrarian people a load of manure from the barn was always applied to the garden every fall. Good ole days.

It's taken the entire winter for the leaves i raked up to even start to decompose, and I've been throwing fruit scraps and used tea/coffee in it every week or so. I keep it stirred and the very bottom layer is a black rich mixture, but I imagine once the temperature rises the rest will decompose very quickly.