For Plip, you may verify that everything is Ok by typing as root 'modprobe plip'. This is purely informational. The laptop is connected to an ethernet network. Plip is not used. Access to the internet is given by a gateway on the ethernet network.
Internet access is given by a ppp connection on the laptop.
On the side of the home computer you must configure the Plip interface. The main difference with Example 2 is that Internet access is given by the home computer and therefore become the default gateway. And that's all. It may be any executable file. I use it to setup my netscape preferences depending on the configuration, but it may contain things like NFS mounting etc.