500 SEL Valve Job / Timing Chain

[Vaden85SEL]

Hi,
I have a 1985 500 SEL and I am afraid the timing chain has slipped one of the plastic rails and trashed my engine. The car will turn over fine, but there is no compression in any of the driver's side cylinders. Other than the engine, the car is cherry and I want to save it.
Assuming that my camshafts are still okay, what sort of job am I looking at? I have heard that the valves will sometimes get bent -- which I think mine are since there is no compression on one whole side.
I guess I am just looking for advice on the best way to attack this issue. Should I yank off the head and rebuild it myself? Or take it to a shop? A new timing chain and rails/guides and tensioner are a given. But what other things are likely to be broken or be in need of replacing? Since I will be so deep into the engine, I may as well go the whole nine yards. I know tons of the vacuum lines will likely snap from being brittle, so I plan on just getting a bunch of fittings and line to replace brittle hose as I go. But what else?
I am in Seattle, and since this will have to be done in an open carport, I plan on waiting until the weather gets a bit better before cracking open the engine -- probably in May or June. Any suggestions or advice will be greatly appreciated. Thanks!