Okay- let's take this one query at a time:
1- "Is roll film the better starting point?"
Oh, yes... Have you loaded cut film holders? Usually we learned on 4x5 inch film holders. They were a bit of a pain, but nothing like the tiny 2x3 holders! If you look around, you'll be able to find rollfilm backs for every size from 2-1/4x2-1/4, to 2-1/4x2-3/4.
2 - "How accessible and practical is the cut film"
You can still buy 2x3 cut film from Ilford (don't... see above answer!)
2 - B: "and where can I get a tutorial or similar?"
Well, any tutorial on loading sheet film is going to be similar for "almost" every size... 4x5 & 5x7 is (in my oppinion) the easiest to load. When you get over 8x10 it starts to get a bit awkward... Larger sheets of film have a tendency to bend while you move them around, introducing artifacts into the film. You can work up to the ultra-large formats, but with a bit of practice along the way!
3 - "Is this Graflex suitable for a variety of photo situations or limited to more specific venues?"
The medium-format Graflex is usable for just about any kind of photograph you want to make. There are enough lenses available to be useful for just about every kind of photograph: 65mm for wide angle, 101 for about "normal", 125mm to 135mm for non-telephoto lenses (with 150mm being the maximum bellows draw). You can find telephoto lenses up to about 203mm (the TeleOptar 8") for a true telephoto.
The Century Graflex is not only a gorgeous camera (especially with the red bellows), but very useful & sturdy (the body takes a lot of abuse- like most of the Graflex's).
You can also look at this site for more info:
http://graflex.org/speed-graphic/century-graphic.html