This is amazing, as much as the voyage novel by itself. Stephen Baxter somewhat repaired a historical prejudice when he wrote that book... true, the Mars plans were gathering dust among NASA archives; someone HAD to write THE novel around them. He did it.
I think if you use SRBS, you will need to extend the S-IC for a proper mount. Of course, it is a model, so make it your own.
The loss was due to a line freezing on the LOX Line as I recall. They put in a bellows to allow it to flex or not flex...I forget the details.