Hungry,
I always add lots of veggies (celery, carrots, onions, whole peppercorns, bay leaves), etc. to the broth while it is cooking. I also save egg shells and add them too. I stick any veggie scraps in a bag in the freezer, like celery tops or leftovers and add them. Jan is quite correct about using the animal parts that have a lot of gelatin in them. The only problem with using a crock pot is the size since they are small, you have to limit the amount of stuff you can add, especially using many bones Add salt to taste at the end of your cooking so it doesn't condense and make the broth too salty. You can strain everything several times until you get the broth the way you like it. I then throw the veggies and bones out, but some people use their blender and then emulsify it and add it to their garden.
I use the broth mainly for soups or sauces. Summer soups like zucchini watercress are my favorite in warm weather. Like you, I do not really want to eat or drink it plain. Love adding leftover scraps of meat or veggies for a quick meal. Italian Wedding Soup is the broth with meatballs and a chopped up green veggie. I almost always slowly sauté the veggies and onions in olive oil until the either "sweat" or are turning brown and then add them to the broth for my soup. Your kitchen will smell wonderful! Remember, the idea is nutrition and clean food. Commercial broths all have undesirable ingredients added. The broth you are making will add the nutrients your gut needs....just like Jan is saying.