There is VISUAL BASIC for DOS.
Serach the web for VBDOS.
VBDOS came with a tutorial that will have you up and running
in less than an hour.
It is real small. You can make a DOS boot disk with a VB Dos
application on it that does serial port I/O to your PIC and displays
pretty buttons onscreen. A harddiskless PC with a floppy diskette
drive locked inside it can be your user interface.
The syntax is QBASIC verbatum so its easy to get help ,books and
examples.
OR
You can use any programming language that can do CGI AND
do serial port I/O and then run a local web server like xitami and
write your user interfaces as CGI web pages.