Frame off-what do I leave,supports, boxing Q's?

[R&B51]

Working front to back frame off and will likely do TCI coil over and 4 link. Will be ~330 HP LS/LQ. What all comes off, then what needs to be added?
TCI pkg front, rear, tranny and motor mounts about $5K, decent rear end with disc another $2K?, front sway$?, does 4 link need rear sway? Added frame support under cab(see below).
Wow, by the time all done, is it better to just bail and go for one of those full frames? Maybe I'm just whining after removing more than half of these crazy rivets!?
So far, all I've left on is brake line tabs by hole through rail and front cross member. I'm back to the round bar across under front of bed looks like park break bar. Since will be 4 wheel disc, assume I cut it out and remove brackets on rail?
What else stays as I cut rear suspension off?
Took seat base out, will need to cut and weld new floor in- any special tasks to make sure front cab mounts are solid? Are repro panels good enough?
Will also weld in new side kick panels and inner/outer back cab corners.
Doing all this, do I need to weld some cross supports across under cab since took out seat base-feels very floppy now.
Ideas or diagrams of what you've done?
Sorry, lots of questions, and will probably be more.
Want it to be super solid, only about 3-4" drop, powerful and drive more like a modern truck.
Previous member said Art Morrison frame was good option if I bail out, any other opinions on ready to roll units out there, ballpark cost?