Easier said than done on 100 acres. Our home has 11, so that was not a big deal despite a few creek-crossings in temperatures that hovered in the low teens. I put on blaze orange to alert any late-season hunters and grabbed some "no hunting" signs.
On the other hand, one could wander in circles for days on 100 acres in Buckingham County and die of exposure. Yet marking one's property is a very good practice. All rural land-owners whose property ends not in fences but in woodland should do it, regularly.
With my brother-in-law and our neighbor Bunny, we trekked the boundaries of the family's property in Buckingham. The family had just purchased two more parcels that had come on the market, so I toted along two spray cans of paint, a compass, and my usual hiking swag. Our property map would not suffice except for vague references; plats may have notes such as "large stone with paint blaze" or "metal rod" with vague (or no) GPS coordinates. In any case, the land is far beyond any sort of cellular reception.
One thing I had forgotten that day was our surveyor's wheel, a must-have for this work.
So usually we walk in pairs or trios.
The most useful part of this exercise was learning landmarks. If you do walk your land regularly, you spot large trees, water courses, and other useful things. We IDed a couple of oaks in decline or in places where they can be felled without hurting the diversity of the forest. With my brother-in-law's little sawmill, we can make boards for our buildings.
We also began to make plans for a few ATV roads we can use to skid logs out. In winter, you can really see the best routes, which are often the old roads that are lost in the undergrowth of summer.
Get to know your land, and get neighbors involved. It's a good way to make friends. Bunny does a lot for us, because we gave him permission to hunt on our property. His help is worth its weight in gold.