[SCOTI]

I even looked into a Chassis as by the time I was done with the whole suspension, brakes, fuel tank and fuel and brake lines and chassis powder coated I am not sure I could get my stock frame even close for similar money.

Apples to oranges comparison. An aftermarket chassis will be way ahead of a 60's work truck chassis that was designed in the early 50's. But, they're expensive. That 60's work truck chassis can be updated to be a much better driving/touring vehicle vs how it came.

I would be happy with stock front springs, tubular arms and a 2" drop spindle. I want the Blazer level so I could start with lowering blocks on factory or tubular trailing arms and the trailing arm mounts with adjustable mounting points and exhaust holes. To get it level I "might need rear lowering springs. I lean towards ride quality and handling over the lowered look.

Tubular arms aren't needed unless they have physical changes done that offer geometry improvements. The standard "they're stronger than stock & won't deflect like stamped arms" is a sales pitch unless you're putting your truck on a auto-cross course or race-track. The original pre-73 bushings don't deflect much & don't bind. Those are two good traits for a touring style of build. Drop spindles for C10's are a good choice as they allow drop w/o compromising the steering geometry. Factory rear truck arms are fine for a mild touring build. Certain tubular arms are worse than the stockers as far as ride quality & binding from articulation. If they need replacing from corrosion I get replacing them. Beyond that? They're only as good as their design.

Are coil overs worth the investment?

They can be if set-up correctly & optimized. If they're just bolt-in swap parts that are designed to install where the original coils went, they're no better than upgraded separate coils & shocks. The main benefit of coil-overs is the ability to easily change the springs 'rate' for tuning on auto-cross & track vehicles. To the average Joe? They're only a benefit if you actually tune or adjust things. If you're a set-it & forget-it guy, there's not much gain if any.

I want quality 4 wheel discs and must have an mechanical emergency brake to pass MA inspection.

There are aftermarket manufacturers (Baer Brakes; Wilwood) that sell compliant kits for classics. There are also aftermarket sources for 'updated' 4-wheel discs (CPP). I recommend reviewing their product lines & finding a vendor convenient for you for the purchase.

Any suggestions? Not wanting a C notch and most the "kits" seem to have them.

You'll only need a c-notch beyond 5" of rear drop. You won't need them since your plan is to keep it mild.