A. This may be useful if you want to install software, such as a service pack, during installation.
Using the Cmdlines.txt file it is easy to map to a network share. Cmdlines.txt must be stored in the $OEM$ directory under your NT installation area, e.g. i386\$OEM$. A very basic unattend.txt would consist of
OemPreinstall = yes
The map command should be under the \[Commands\] section of your cmdlines.txt file, e.g.
".\net use <drive letter>: \\<server>\<share> /user:<domain>\<user> \[<password>\] /persistent:no"
It is important to add the /user otherwise the system will attempt to use the System account which does not have an actual user account thus the command would fail. The /persistent:no is used as the connection should not be remade at each logon.
One option would be to enable the Guest account and give it access to the share which would mean you could connect at /user:<domain>\Guest which would allow a connection to be made to the share even if the domain controller cannot be contacted.