What will happen when the PC moves inside corporate network – when there is no VPN?
You should deploy some other NAP enforcement (like DHCP, 802.1x or IPSec) inside your corporate network to take care of this. The beauty of NAP architecutre is same set of policies can be applied on the same PC when connecting over different enforcement. For example, when the laptop is at home, VPN NAP is enforced; when the laptop is inside corporate network using wireless – 802.1x can be enforced; when the laptop is joined to ethernet using DHCP – DHCP can be enforced; etc.