The last couple mornings when it's been cold (20F) I hear a
"chick-chick-chick" from the passanger side of the engine, too slow a sound to seem to be a belt/pully issue. The sound goes away when warm.
Is this the classic exhaust manifold gasket going bad syndrome?

99 Mounty V8 75K miles..

How much of a PITA is it? Can most of the work be done from the wheel well?

V8 manifolds are known for having the bolts back out, you may just need to tighten them up. I think a few people have had issues with them cracking. Do a search the info is out there.

I have that ticking sound too, but mine never goes away. I noticed that I had one of the passenger exhaust manifold bolts really loose and needed to be tightened. I reached my hand to tighten it and the bolt and stud completely fell out. I put it back in and tightened it, but it didn't do anything with the ticking sound. Just something to consider. For me, it's an excuse to start saving for some headers. :D

Mines been ticking slightly since I bought it. And when I changed the pulley on the SC it got worse on the first WOT pass. I tightened the bolts on the passenger side and still does it. Bought some headers though with some copper gaskets and Stage8 bolts. I'm putting a stop to it.