Broken camshaft, what else to replace?

[dr.no]

I've had a valve tick for a few days, that got better with adjustment (two tight exhaust valves) but didn't go away. In retrospect, this was probably the vacuum pump instead...
While driving I had a sudden loss of power, with dark smoke, then a few blocks later complete cessation of engine action.

When I got the valve cover off, this is what I found.



Broken just in front of the second tower. All the valves are closed, the engine spins with no clanky-clanky sounds (and it quit with no bad sounds), so I hope there is valve-meets-piston damage. The first tower is sheared off.

This thread on here raises my hopes: Broken camshaft: 617 '81 SD. How could this happen?
So, I'm hoping to replace the cam and towers (and VP), and since I'll have to re-time the whole thing I might as well replace the chain. And as far as I know none of this has been done and there is a little seepage, might as well do the head gasket too. And valve seals.

What else? chain tensioner, guides (didn't seem out of spec on Friday, but...). I'm not exactly looking forward to the timing experience, so have a lot of reading to do. I can set pump timing on VW diesels with my eyes closed, but these are entirely different beasts.