
Another example of "Everything's big in Texas!" It's too small for David, and too big for me!

How big is the right size is, of course, relative to the size of the job. A 45 HP tractor like that begs for a large mower in order to be able to mow fuel-efficiently. Put a 5 foot mower deck on it like I use, and it'll burn 2x the fuel needed for the job. If you have a large enough area to mow, you can throw a 15' or so wide mower on the back of that machine and really make time.
Here's what (on the big side of jobs) I know that 45 HP tractor would be able to do, GW:
-Pull a 3 bottom plow
-Run a small or medium sized round baler (up to maybe 1500 lbs bales)
-Handle a three-point backhoe attachment on the back (with front end weights)
It will of course handle smaller jobs, too, but less efficiently and more expensively than a smaller tractor. If possible, figure the size of your work and buy to match.
I too doubt anything that big has hydrostatic drive. Driving a stick on a tractor IS notably easier than in a car, because one rarely has to change gears while moving. You can start from a full stop in any tractor gear. Maybe that would make enough difference for Cindy; it does for my Son.
Some comments on that particular tractor:
-Box blades are wonderful for dressing gravel driveways and top dressing fields. My wife loves hers.
-That front end loader has seen a fair amount of use for 756 hours. Note the left front tire is low. It IS possible to ruin a set of front tires with hard and/or inattentive front end loader use in even less hours than that. So check out those front tires for damage, wear, and leaks if you look at buying it. The good news is, front tires are a lot cheaper to replace than rears.
-Trailer looks nice. If it's in good shape, it's useful for lots more than just hauling the tractor.