Congratulations!!! I've owned two of those JD750 tractors, a 2whl drive and a 4whl drive, and they are very well designed machines that will give very good service and have excellent reliability. Neither of mine had loaders, so that's why I have a 790 now, plus I wanted to move up in size too.
I'm sure the engine oil dipstick is on the side of the block, just can't remember which side. Also, I believe the transmission/hydraulic fluid dip stick is a yellow cap somewhere right around the shift lever, but again this is going by my not so good memory. I think you have to screw it out, it doesn't just pull out. The fill port for the front axle is also a yellow cap that you have to unscrew to check it. The only other thing to check on is the radiator fluid and I am sure you can figure that one out. Do get a manual for it, you will be glad you did.
Good luck with it and hope you get great service out of it!! Oh yeah, pictures are required, or else you're just pulling our leg!!!
Edit: I just noticed that if you go to the JD owning/operating forum there is a thread there about JD750 manuals for sale on the big "E". Might be something to think about.