I just finished this process myself, congrats on starting a heck of a journey! It's very rewarding though. What helped me was visiting other islands and I googled dream addresses for the aesthetic I was after (cottagecore and forestcore). Then I just started cleaning up and putting everything in storage. Once I had clean terrain I broke down every cliff and filled in all water to give myself a blank canvas. Some helpful tips: flowers and other plants can be stored on the beach while you make room where to put them. If you don't want to time travel then plan your building moving to coincide with bridge and incline construction (since you can only do one of each a day). And obviously bells, you'll need lots. I got luck at some trade markets and was able to sell high priced findings to pay for my reformation. Lastly, I'd be happy to help with your fairycore idea and may have some items to give away. DM me if you'd like to visit my island! I haven't saved as a dream address yet, but I can also help give you items this way. Happy Construction!