Those devices that are only b/g will use it, the router supports all three standards at once. So no problem there. Remember that the router in question is probably a home user router, you won't find this kind of equipment in a business environment, unless it's just a normal office, then sure, you can learn with that.
Regarding Windows server 2008 r2, you can learn a lot by yourself.... When it comes to FTP servers, there are many different solutions... there is the standard MS FTP Server, and of course many third party ones... Serv-U is an example....I think you are best of learning this on location.