There aren't many options when confronted with a few dozen pounds of fresh beets. Like most root crops, beets store very well and can last for months in a cool, damp medium, but even then they have a finite shelf life. Pickling can extend that shelf life dramatically.
For eating, most sources recommend beets be harvested while still quite small. For pickling, you can get away with beets being a little larger. Three-inch beets fit canning jars very well. Fresh beets should be pickled; throw any limp or soft ones in the compost pile.
After selecting and harvesting your beets, wash and scrub them well. Cut off the greens leaving one to two inches of the stems in place. Leave the root intact or trim off just the end to minimize the red bleeding out.
Put the beets in a large pot, cover with water, and boil for 30 to 45 minutes; less for small beets, more for larger. Beets are quite dense and boiling helps soften them for the pickling process.
After boiling, place them in an ice bath or rinse with cold water. This makes it easy to remove the skins, which is an important step. Cut the stems and roots off and remove the skin. You can peel the skin with your fingers, rub the beet with a paper towel, or use a soft cloth. Your fingers will get red from residual juice but it washes off easily.
After the beets are cooked and skinned, cut them into slices about 1/4 inch thick and place them in a pot of hot pickling solution.
After combining the vinegar, water, sugar, and spices, bring the solution to a boil over medium heat and boil gently for 10 to 15 minutes. Discard the bag, if using one. Add the sliced beets and return the mixture to a boil.
Using a slotted spoon, place the beets in prepared, hot, canning jars, leaving at least 1/2 inch of space at the top. Ladle in hot pickling juice, leaving 1/2 inch headspace. Use a plastic tool or spoon to remove air bubbles and add more liquid as necessary to maintain 1/2 inch headspace. Wipe the rim of the jar with a moist paper towel, place a lid on the jar, and secure it finger-tight with the band.