Preheat oven to 400°. Line a large baking sheet with foil or parchment. Leave the potatoes and beets unpeeled. Place vegetables onto the prepared pan and cover with foil, sealing the pan tightly. To cook the beets faster, wrap them individually in foil and seal tightly. Roast the vegetables until fork tender. About 20 minutes for the carrots, 30 minutes for potatoes, and 45 minutes for the beets. This step can be done in advance to allow cooling time.
Once the vegetables have cooked, remove them oven and cool completely. Once cool, peel the potatoes and beets and dice into pea-sized pieces. Dice the carrots, pickles, and shallot. If using frozen peas, thaw them in hot water.
Combine all of the vegetables and dill in a large bowl; add the sauerkraut if desired. Season generously with olive oil, salt, vinegar and small amount of reserved pickle juice. Toss all the ingredients turning from the bottom until well combined. Taste and adjust oil, vinegar, pickle juice, salt and pepper to taste. Refrigerate if not serving immediately.