For totally generic games that boot straight off the floppy disk, the default config tends to work just fine. Like I said in my other comment though, I used a temporary config file, based on the default config, but I would append the boot image filename/path to the [AUTOEXEC] section at the end of the temporary dosbox.conf file.
It might be easier for you for now to make individual config files for each game, but it should be possible like I said to make a generic script to boot basically any PC floppy disk image directly.
I'll see later whatever I have around.