Here are the rules I’ve merged from kitnkabootle, abbyblueflower and JojoMOMSTAR. (Edited again: 29 December 2020, 11:15 GMT)
Overboard, Stranded and AloneAn Off-the-grid Island Living Challenge
You were on an ocean liner when everyone abandoned ship due to a fierce storm. You held on to a raft for dear life until you were tossed on a beach on the remote island of Sulani. Everything you have is lost at sea. To survive, you have no one to count on but yourself. Take charge of your fate. Challenge the elements, challenge yourself and find your way home.
Key Points to Being Stranded in Key Point- Start by being stranded in Key Point, Sulani (Hard mode: have more than 1 Sim*, e.g. toddler and/or a baby, and/or a child and/or a teen**)
- Keep lot traits to Ocean Paradise and Off-the-grid
- Set funds to §0 to start the challenge (Hard mode: earn §10,000 to build a home fitting
Off-the-grid Island Living aesthetic)
- Survive alone on Mua Pel’Am (or Key Point until you reach Fitness Skill Level 3 for endurance swimming with Hard mode) until you can get an Outrigger Canoe to explore and travel beyond Mua Pel’Am****
- You are unemployed as you’re disconnected from the world and can only do odd jobs–until you built a home (with at least a bedroom, a bathroom, a kitchen area and a pier) and own a canoe*** (1 canoe = 1 YA/Adult Sim)
- (Extreme mode: you are not allowed to sell anything except for fish and duplicate collectibles until you unlock a canoe and open up trade with locals you find)
- There is no phone use or socialising with wandering Sims or leaving Key Point until you get a canoe!
- Earn §§§ by doing odd jobs (Hard mode: one odd job a day) and/or
- Beachcombing
- Fishing
- Gardening (Hard mode: Only use Sim-made planters)
- Paintings - Sims must autonomously start painting, only allowed during the day
- Woodworks - sell 3 a day (Hard mode: sell 1 per day)
- Writing books is against rules but Sim can keep a journal
The Route to Rescue and Beyond (Milestones & Aspirations)- Achieve Beach Life to become a true local and unlock marriage.
- Achieve Well-off (3rd milestone of Fabulously Wealthy) and Estate of Art (1st milestone of Mansion Baron) milestones to
- wire electricity into your home for §25,000 (Hard mode: Complete Fabulously Wealthy & Estate of Art Aspirations to buy electricity for your home costing §25,000)
- Achieve Garden Variety (2nd milestone of Freelance Botanist) to prove you Sims can buy good produce (fruits, vegetables and flowers) from you
- Achieve Ill at Easel (1st milestone of Painter Extraordinaire) and reach Level 4 Painting Skill before you can sell your art
- Achieve Fine-Tuned (2nd milestone of Musical Genius) to unlock better music for others to give you decent tips
- After building a home and completing an Aspiration (as well as the above), you have the freedom to do leave Sulani and go back to on the grid or stay off the grid. Or a bit of both.
- You can buy a canoe if you’ve got the funds or build your canoe (Hard mode: Get a canoe after reaching Fishing Skill Level 10 & Handiness Skill Level 5). Sim must complete a milestone (Hard mode: Every YA/Adult must complete a milestone) made possible without the use of electricity.
* - There is no daycare, Sim toddlers must go be with a Teen/Adult but Sims babies cannot go on the canoe and must remain on Key Point.
** - If stranded with children and/or teens, they cannot go to school until a YA/Adult has a canoe. (Hard mode: Until a basic home is made)
*** - You can buy a canoe if you’ve got the funds or build your canoe (Hard mode: Get a canoe after reaching Fishing Skill Level 10 & Handiness Skill Level 5)
**** - Sims cannot go to the hospital or anywhere that requires the loading screen to travel. (Hard mode: Sim can’t go out of Key Point to nearby Mua Pel’Am islands until reaching Fitness Skill Level 3 to make sure they don’t ‘drown’)
General Rules- Cheats are not allowed unless turning funds to §0 in the beginning and if you choose to pay for travel around Sulani (e.g. weekly boat pass).
- Mods are welcome as long as they don't make things easier
- Reward traits and items are allowed except for Potion of Youth and Money tree.
- Father Christmas visiting you is optional (as a result of island fever/hallucination or because stranded Sims need all the help they can get)
- Turn Celebrity Off for the household if you have Get Famous EP. If you want to be a Celebrity, you must complete Friend of the World before turning it on.
- You may choose or randomise your Sim. (Hard mode: use Child of the Ocean and because 'fish are friends, not food' ups the difficulty).
- Choose your difficulty by choosing your life span.
- Once you have electricity you are free to do as you please, you have succeeded! Return on the grid and back to your Sim’s life before or off the grid, or a bit of both, you choose!