Lilleekitty8 I've literally just done something like this with Island Living and Eco Lifestyle. It's been such a fun project. If you have these packs here's how I did it. I have a family of Island guardians consisting of a brother Keanu and his sister Leilani. Keanu has a family and he cares for Mua Pel'am. I split Leilani from his household with just enough funds to buy Reef Finery in Lani St. Taz, which was bulldozed. She had absolutely nothing to her name except that deserted beach lot. I decided she'd earn everything from the land and make her own furniture and decor too, it has the Simple Living lot trait and she grows her own food.
I set strict rules that she wouldn't buy anything (except the purchases for the Nature's Calling Event). She fished and beachcombed at first to survive. She's travelled across all my other worlds (with the full game) collecting, fishing and harvesting and planted harvestables she found on her home lot. I have an Arts centre in Evergreen Harbour where she could craft her own furniture and decor using the fabricator and woodworking table, easel, pottery wheel, flower arranging table and more. She's also raided the dumpsters and restored or recycled her findings. She even made her own jewellery from Sapphires and Silver that she collected and I made her tattoos by hand too. She found her dog when staying in Moonwood Mill off the grid.
She now has a full garden with all harvestables, no seed packets bought for them she harvested them all herself. All I needed to buy were walls and floors to build her wooden stilt house. I used glass walls instead of windows to save money. Now that she's financially settled I'm replacing some of her fabricated furniture with wooden furniture from Enchanted by Nature.
Previously when I've done this I've "shipwrecked" a Sim in Mua Pel'am with no money and they've made a living from collecting and gardening and then moved into a house. This is the first time I've had a Sim make her home by hand. I was going to keep the fabricated furniture but it had too much of a modern look for her wooden home, but it served her well and she has enough money now. But most of her home is still hand made. I just replaced the bed, indoor dining, kitchen units and seating items. The Natures Calling Event items from the woodworking table look really cool in her home too. She's even knitted her own rugs! Her kitchen appliances were restored from the Restoration Workshop kit except her sink and pressure cooker which were from dumpsters, as was her bathroom.
I loved Castaway too that's where I got the idea for my Shipwrecked Sims.