Just an update to close things out on this thread - on the F77 front, I was pointed to the RT11 layered products directory on trailing edge. There are several F77 disk images there, but basically they are all F77 5.0 except for one set (f77v5b) which is F77 5.0A. I also corresponded with Bob Walraven, the person who did the conversion to RT-11 back in 1984. He was able to provide an RX50 distribution set which is also v5.0, even though, as noted below, the disks are labeled "V1.0".
Bob's disks are labeled as follows:
BL-BR74A-RC
F77/RT-11 V1.0 BIN RX50 #1
(C) 1984
MULTIWARE, INC.
LIC TO DIGITAL EQUIPMENT CORP
and
BL-BR75A-RC
F77/RT-11 V1.0 BIN RX50 #2
(C) 1984
MULTIWARE, INC.
LIC TO DIGITAL EQUIPMENT CORP
Bob worked with the original DEC BLISS sources and rewrote the RSX-specific routines in MACRO-11 to work with RT-11. As a result, the core compiler functionality is identical. The Multiware docs are posted on bitsavers.
I also recovered a couple of versions of RATFOR (Selzer and Denny) but haven't been able to get them to run yet, though with F77 available, this is pretty much a non-issue.
Thanks everyone, for your help.
Jack