Crew C30 vs C20 differences

[kevinr1970]

I am under the understanding that all crew cabs share a "1-ton" frame.
I also understand that a C30 came with a full-float rear while a C20 came with a semi-float rear, but the semi-float is unique to the crew due to the spring perch and shock mount locations?
I am I on the right path here?

So what is different on the front?
Are the Crew C20 and C30 the same upper and lower control arms, or are the lowers different?

I was told that the only difference on the front of a SRW and a DRW was the rotor, but have never confirmed that.

I am going to convert my C30 Dually to single (and short bed eventually) and there is a guy parting a C20 crew.
I have Belltec 3" spindles on my crew now, so I can't just swap all the front end parts over.
Just wondering what all I could grab off this to help me convert to SRW.