Hi Russell
Congratulations - have fun. I'm just a dabbler, by contrast with most people on the list who seem to be IT professionals.
I had a similar experience to you - I was astonished to find a desktop after doing my first install! Not at all what I had expected from the recommended Linux books. All the same, the command line is essential - especially being able to switch to a different console when things go a bit wonky...
Some things are easiest done with a GUI - like file copying etc, as you mention - many things can really only be done, or are best done, at the command line. Basically there are a huge number of things to learn and you will just have to pick them up as you go along.
Mandrake tries to make it easy and approachable for the inexperienced user - the more experienced find it frustrating for that reason but for many people a lot of hand-holding and being able to do fun things right from the start is a good place to begin. But at some point we all have to start reading and studying and trying things out and breaking them and then trying to find out how to fix them <grin>.
I do suggest that you look at the Mandrake support sites, especially http://www.mandrakeuser.org which has a lot of helpful, detailed, easy to understand information in the document section. They are useful for any inexperienced linux user, not just MDK users, as are the Suse and Redhat online support. The mandrake user and refrence guides are also invaluable.
Best wishes, ask away when you need help - as long as you're making some effort to work things out for yourself then people will be very glad to help.
Regards Syd