If the home has vinyl siding I will in alot of cases remove the vinyl siding and install the cat5 cable behind it. They make a siding removal tool that makes removing the siding very easy. You can pull out one section, put in the cable and put the section back. In cooler weather the siding can be a little brittle so you have to be a little carefull.
I have also done this with coax cable. Makes for a clean installation.
