Here two ways that I can think of:
A) Buy Fanuc OLPCPRO software which is way cheaper than Roboguide. This software runs on your PC like Roboguide and you can open and edit TP programs.
B) Save your programs as LS file and use a text editor to modify it. Now you need ASCII Upload software option on your robot controller in order to be able to load text (LS) file. Check to see if this option is already authorized on your robot or you have to buy it.