John,
I don't have the Cub you're referring to but I do have that York rake.
Some thoughts:
I wouldn't expect there to be any problem with that tractor being able to pull the rake.
The driveway should be a piece of cake.
Lawn expansion... I'm assuming you'll be using the rake for both finish grading as well as rock removal. The rock removal is the only thing I'm mentally questioning. For efficient removal, you'll have the rake angled and keep pushing into a bigger and bigger windrow for easier collection. Like snow, the faster you're going the better so they slide off to the side. Not sure how fast your tractor is but I would recommend going about as fast as it'll go. (Personally, I use an ATV)
Take a look at the attached picture. Although currently connected to a small aerator it was built specifically for the York rake. The little trailer "thingy" is used between the tractor and the rake. What it does is create a "buffer" area between the pulling machine and the rake for 2 reasons:
1 - Especially when the rake is angled, when you turn it allows for a sharper turning radius since the rake can't reach your tires.
2 - When doing rock removal (lawn expansion), if you catch a rock or something sticking up (but too much for the rake to grab) the rake will jump. If the rake is angled, Murphy's law says the jump will always make the edge closest to your tractor jump forward. Again... rake hits tires or somewhere on the tractor.
Brian