Probably looking at a compact in the 30-40hp range.
Seems about right.
FLUSHER has given good advice:
Tractor: 30-40 hp (engine), hydrostatic (HST) tranny, 4WD, power steering,
ag tires with rears filled with liquid,
dual rear hydraulic remotes,
front end loader (FEL) with 5-ft wide bucket, skid steer quick attach on the bucket, chain grab hooks on the bucket.
Mower: 5-ft brush hog.
I would differ only in recommending UNLOADED R4 Industrial Tires, rather than LOADED R1 Ag Tires, as you will want an FEL and the potential for turf mowing around a home is there. I do not remember clay as being the dominant soil type around Huntsville and, as a non-farmer you can delay tractoring a day or two if the soil is too wet. (Tires are always a close call.)
You will probably want a PTO powered roto-tiller and a 3-Pt. mounted cultivator for your garden.
Huntsville is a pretty affluent area. I expect you have a wide choice of tractor dealers not far from your property. With transfers in and out of Redstone Arsenal I expect used low hour tractors become available regularly.
One caution: Stay away from the pond. Ponds suck in tractors.
Here is an IMPLEMENT LINK:
http://www.lsuagcenter.com/NR/rdonl...45263BDD8/11557/pub2917tractorimplements1.pdf
Alabama and Mississippi are home to most USA implement manufacturers.