This is what the transport map of Westeros would look like, if the Game of Thrones universe had public transport.
There's also a map of the whole known world's transport...
...Although Essos isn't quite as well served in terms of infrastructure.
Naturally, most routes lead to King's Landing.
The Iron Islands have a ferry route as well.
Sadly, lots of the stations on The Wall have been shut.
And obviously the route to Valyria got closed down a long time ago.