Why have you tagged your post FTP ? do you really need FTP ?
If you have credentials for the server, you have two options
a) create a permanent share on the server where the files you need are located, then create a permanent map to a drive on your work machine
b) almost as per (a), but map a drive to the server/share when you need it - forget the forms based sample in the link that follows, look at the example code - you can create and take-down a share dynamically
http://www.codeguru.com/csharp/csharp/cs_network/windowsservices/article.php/c12357/C-Map-Network-Drive-API.htm[
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as for the 'best method' - if you're on an internal network and the server is 'stable', either options is good