Ordering of repairs / upgrades

[42corsair]

I am in the process of building a project schedule for my recently aquired 72 C10 LWB and just wanted to get some opinions on ordering - I am running into several items that are all connected - specifically in the rear end

For instance, I know I want to replace the stock exhaust system with a flowmaster system. Simple enough - however, I also at some point want to install a bag system which would include a new crossmember with holes for the exhaust to run through.

Should I try to do these at the same time? Or is the time/effort/$ invovled in relocating the exhaust through a new crossmember not worth it?