</font><font color="blue" class="small">( Eventually I would need to add more fencing and smooth out/groom the forest roads as well as adding some more trails for riding.
I guess those tasks calls for a FEL and boxblade.)</font>
I've been using a TC33D w/ 5' brushhog and 6' boxblade to maintain 1300'+ of gravel road/driveway, and to create/maintain trails in our woods for walking/XC-skiing/horseback riding. I find the size works well for me. I would have gone larger (we have 80+ acres, plus help our neighbors with their 30 acres), but was concerned about maneuverability down some of the trails through the woods. The only thing I still have a tough time with is figuring out an easy way of dealing with the sapling stubble after brush-hogging. Once the trail has been established and kept up for a couple of years, it's not an issue, but that small stubble could wreak havoc on a horse's hoof if they stepped on it wrong. Often the boxblade will clear them out, but not always.
</font><font color="blue" class="small">( The largest building entrance is 12x10, while the smallest one is 8x8. I'm not sure I'll ever want to get a tractor in the smaller one, as there's plenty of storage/workspace area elsewhere.)</font>
The mid-sized NH CUTs (TC29 & TC33) will fit through an 8 x 8 door with no problem, you don't even have to fold the ROPS down (that's the size door I put on the building where I store my TC33D). Personally, I would not go much smaller than this for the tasks you describe... unless one of your PRIMARY uses was to manuever in tight spaces inside your buildings, for example). JD 4300/4310 is similar size and capabilty, as is the Kubota
L3010 (I'm not sure about the newer Kubota 3130... I've heard it's a bit bigger than the
L3010).
</font><font color="blue" class="small">( Do I need to worry about the tractor & implements crushing my septic system in one of the side fields? )</font>
Many folks drive right over their tanks and leach fields. I do not. It's not just a matter of crushing it. That's possible, but rare on a properly installed system. You also have a problem with soil compaction. Over time, this can greatly reduce the capacity of your system to handle wastewater flows. You can minimize this by keeping your equipment as light as possible, and not driving over it unless the soil is thoroughly dry. I have an old Craftsman garden tractor (i.e. a glorified riding mower) that I've kept for mowing up near the house and over the septic system.
John Mc