I don't know where you found your information that printing to tiff is a sepeate piece of software that you need to operate, because my searches "windows print to tiff" and "tiff print driver" both found tiff printer drivers for windows that "ANY" software can print to just as if it were a HP or lexmark printer...
and yes it is possible...
1st) Download and setup tiff printer driver and make it the default printer driver..
2nd) shellexecute API with "print" verb the *.pdf file in question
3rd) Download and setup if needed WIA 2.0
4th) Use WIA 2.0 to open and display tiff image in picture box
Good Luck