I've found people can assume all kinds of things no matter how hard you tell them its a prototype. You have to use clear language saying it's a prototype and the contents will change - and even then some will discuss why the map looks bad lol! Personally I would get it looking as close to the real thing as possible - use 3D design or 3D print to create mockup parts, or hand make it, - it's the design and style that attracts a lot of people whether it's a beautifully hand printed cloth map or a plastic rocket, it's these things that get people excited so spend the time to make them. Cancel that friday night out where you'll spend the cost of making the 3D prints you so desperately need but think you can't afford. It's all or nothing when you get to launching the project and everything you can show up front or reveal through the project will give you so much more to say to people. People are visual and need cool graphics, awesome models, 3D visualisations - not walls of text. You don't need it to be production ready, it just needs to look cool!
It should have the look, shape, and functionality of the final product, with 10% wiggle room for creative suggestions from your backers. If it's 75% complete... not enough. If it's 100% complete there's no creative process.
I speak from a Gaming Genre standpoint, but I think this still applies. Mega companies like Pebble Watches do better to show a complete product; but even then... colors of watch bands? There's always something you can let the Backers participate in the product's final design.
Always leave room for flexibility. For me, the thing that makes Kickstarter beautiful is feedback from your backers. These are people who are SO excited about your idea, that they are willing to help you bring it to marker with the promise of the final product. Allowing them to help shape the idea makes them that much more excited.
However, be careful with the changes you make. You don't want your project starting as one thing and turning into another. I would say 80-80% is a fair starting point. It means your core project is shapes, but the remaining 15-20% will evolve during the campaign. Evolution is natural and amazing!