What areas are most difficult to disassemble/assemble in cab?

[71CHEVYSHORTBED402]

I'm a 53 year old beginner. Owned this truck since 1989. So easy to love these trucks.

I was hoping to get a mechanic over here. That hasn't worked out so far, but it will. I'm counting on it for the suspension, mounts, steering column, gear box, some of the firewall, some wiring, maybe a flex plate and rear main gasket. I think I can do the rest, we'll see.

At any rate, I've been tearing at it anyhow, removing everything possible while allowing it to run. At some point it's going to sleep. Everything but the engine and tranny are coming off. Taking very good notes as I go (wrote systems requirements for 10 years.........it pays off...ha!). Packaging everything up. I won't reassemble for well over a year. Surprised how much time required just to stay organized.

I've just started digging into the dash. Next up is the temp. control. Have NO idea what's behind that instrument cluster, but I'm sure it's "fun". Anyway, what are the most difficult components in the cab? All advise is appreciated.