for those of you thinking about going the 2018 match schedule has been released (in july this year)

http://resources.fifa.com/mm/document/tournament/competition/02/66/71/62/150713_2018fwcschedule_v10_neutral.pdf

note Moscow, St Petersburg, Kazan and Sochi are also hosting matches for the 2017 Confederations Cup


a map showing the location of the host cities is on Wikipedia

https://en.wikipedia.org/wiki/2018_FIFA_World_Cup

With the exception of 'H3' all of the teams will have at least one 970km (by comparison Sydney-Melbourne is around 963km) plus journey between the first and second or second and third matches