Short version: Uber with solar-powered golf carts on an uninhabited island in the Caribbean. Eventually autonomous solar powered golf carts.
When I was 16, I dreamed of building a passenger rail network on Little Inagua. 
My ideas have evolved a bit over the years, but I still fantasize about building a free colony on Little Inagua. One of the reasons I love this island is because it’s big, flat and receives lots of sunlight. In one sense, it’s a bummer there are no mountains, because I find mountains beautiful. But the flatness presents a great advantage in terms of construction. It takes much less energy to move heavy things sidewise on flat land than over hills or mountains. Another cool feature of Little Inagua is that it’s made of fossilized coral, meaning CaCO3, calcium carbonate. 
The main use of calcium carbonate is in the construction industry, either as a building material or limestone aggregate for roadbuilding or as an ingredient of cement or as the starting material for the preparation of builder’s lime by burning in a kiln. -Wikipedia
Which means the island itself is a great foundation for any structure, and all we need to do to build a road is clear the brush and boulders. We don’t have to lay any asphalt or concrete! We could use my basic routes from 2006, but rather than laying rail we can simply clear the paths. Then we could drive around the island in solar powered golf carts which we could build for a few thousand dollars each, meandering between hanging with friends and doing light gardening chores and fishing and playing disc golf, occasionally building structures and repairing infrastructure. https://youtu.be/pE44sAzAQuQ Maybe 2017? Even though there aren’t any mountains, this is a pretty beautiful place to live.
If you’re interested in ideas like this, you’d probably enjoy my book, The Sailboat Diaries: 
Order/Download “The Sailboat Diaries” by Michael Fielding
http://youtu.be/ChLQxHX6PsA
