My mom and I recently started building in the frontier, we have 3 quite small islands we are building on. Me and her are working on it, her Name is Nevicyn and mine is NamiMay. We went quite far away from the outpost and we are spaced out to other peoples places too.
Unfortunately you don't meet the set criteria, try going further out. You are currently just over 2000 blocks from the closest spawn.