The answer really is "it depends on the country". There are different kinds of rural and metropolitan areas. How do people live in rural France and how do people live in rural Mongolia? Is living in downtown Singapore really the same as living in a favela in Sao Paulo?
For example you mention that your assumption is that most countries have suburban areas. Suburbs (in the North American "sprawl" sense) isn't really a phenomenon common to all countries: https://en.wikipedia.org/wiki/Suburb
Here is a list of countries by the ratio of urbanization (also has present ratio of urban population):
https://en.wikipedia.org/wiki/Urbanization_by_country
But, the numbers in the above table don't tell you much about and how the place actually feels, so try using Google Maps and Streetview and "visiting" the places to complement the table. Try starting downtown, pick a road and start clicking down it until you are in the countryside :)
If you are looking for a really good source on "how to draw a map" of a world, check out the Dungeon Master's Guide for Dungeon's and Dragon's 5th edition. Its setting isn't science fiction at all, but it has very insightful and concrete discussions on how to draw/write a map of your world. For example, it describes how you would expect villages to clear most of the immediate woodland for farmland, and in the centre of villages there would be a nobleman's keep and his soldier's barracks that would keep their lands safe from invaders in exchange for tax. Another town's purpose could be as a trading hub at a river or crossroads of two large roads, and there would be less farmland surrounding that town because it can get food by trade.
The point is that if you think of who is in your world, you will be able to easily understand what people living there would do to its terrain, how they would build their cities and use resources. You won't have to design your world, you can let its inhabitants do it for you!
