whats the easiest way to remove the back exhaust manifold on a 99 grand caravan

Easiest way is to let someone else do the job. That job is a S O B.

If the labor cost is the issue, and if you willing to do it yourself, remove the wiper, remove the wiper housing whole assembly, then you have more access to the rear manifold, try it, it may help

I was at the point you described working on ac so thought I would change the gaskets and plugs while I had access or a little more access. TY for an intellectual reply.

Was to Darwine TY.