Is there any way to utilize fonts without having to install on the printer. Currently, we go through the install and restart procedure, but it would be much better if the fonts could be utilized in a manner similar to how Distiller uses them by pointing it to look in specific directories for fonts.

Place the .pfa font file in fontlib, then include the following code in your JDT, adjusting for font name and file name:

 mark
FontDirectory /Zip4DeliveryPointBarCode known not {(zip4dpbc.pfa) RUN} if
cleartomark

or much better do it the "VIPP way":

[ /Zip4font (zip4dpbc.pfa) ] null SETENCODING

or apply any encoding table instead of "null".

Using the "VIPP way" for PFA / PFB fonts is it also possible to specify a kerning (AFM) file for the font?

The VIPP reference manual shows an example of
/vipp_font_name [ /PS_font_name (AFM_filename) ]

Can these be used in combination? or can kerning files only be specified for postscript fonts loaded on the printer?

Yes. IOW:

/vipp_font_name [ (PS_filename) (AFM_filename) ]

is valid.