Goodyear carbon fiber ATV drive belt

Good morning, I am new to the forum. I'm 75 years old and love getting ATVs back to usable condition. I particularly like the 2006-2009 Arctic Cat 250 Utility. I currently own 6. The 2006 I am working on only has reverse and low gear. The "drive shaft" in the transmission is completely stripped where the high gear would mesh. Has anyone on here replaced the shaft. I'm told I have to split the case. I was hoping that someone on here could let me know how hard it will be. I already have it stripped down to where the shaft coming in from the clutch side is the only thing left. I was hoping I could just remove the driven clutch and drive it out from there. Directions say different. Any help would be greatly appreciated.

Hi Guys,
We've just removed a Gates belt from a cforce 1000 touring and it looks like an egg shape and we leave it on the side for about 1 week and still didn't got like the normal oval shape, any thoughts on this? Do you think it's normal?

Which is more reliable? Shaft or chain drive? 

In search of my first ATV? What are good older 4x4 models?

So I decided to pick up a small trailer if I could get one for the right price.  I found this one for a few hundred bucks on Craig’s list.  It is  a galvanized trailer which is exactly what I was looking for. The wood was shot and needed some minor repairs which I could care less about as long as the chassis was good. 
I striped it down and put a new deck on. I had some vinyl realtree graphics that I had laying around so I added them to the fenders which I think worked out well. Very happy with this little guy.  
I'm having the iron workers at my jobmake me up a few lightweight side rails that will have a 22 degree bend in them to accommodate the tires that slightly hang over the edge and will incorporate some tie down points as well.