MENU.BAS is actually the word processor program.  Why waste time having
MENU.BAS load another program?

Because it is written in BASIC, the editing is pretty pokey; it is very
easy to type faster than the program can accept it.

I haven't played with it much, but I'm guessing the file DE.RND is the
program having its own implementation of a directory structure, as that of
FCS is pretty poor.  The text which shows up on this disk when the program
runs is some gibberish which starts at sector 64.  As the FCS directory
shows nothing there, it does tend to confirm this suspicion.

Looking at the code, the key mapping seems to be:

CTRL-C --> line 1400  --> create 1-9 blank lines before current line
CTRL-D --> line 1900  --> delete 1-9 lines (current and successive lines)
CTRL-E --> line 1300  --> insert char
CTRL-H --> line  600  --> home
CTRL-J --> line  700  --> cursor down one line
CTRL-K --> line  800  --> kill (erase) line
CTRL-L --> line  500  --> erase page
CTRL-M --> line  900  --> carriage return
CTRL-Q --> line 2000  --> set parameters:
                             line length, paragraph indent, lines per page,
                             pages in use, straight right margin,
                             printer baud rate
CTRL-S --> Line  200  --> save page (requests page to save to: 1 to 9)
CTRL-T --> line 1500  --> load page N (1-9)
CTRL-V --> line 3000  --> ??
CTRL-Y --> line 1000  --> move cursor right
CTRL-Z --> line 1100  --> move cursor left
ESC    --> line  180  --> exit program  (prompted to confirm first)
chr 28 --> line 1200  --> 
'^'    --> line 1800  --> 
DEL    --> line 1600  --> delete char

'a' - 'z' --> line  400  --> insert at cursor (displayed uppercase in yellow)

space, ! " # $ % & ' () * + , - . / 0-9 : ; < = > ? @ A-Z -->
    insert character at cursor