I'm a novice traveler and am having a real hard time figuring out the rail system and how I'm supposed to get from London to Edinburgh. I'm flying into Heathrow arriving on June 11th (I wish I could fly straight to Edinburgh but the flights are way too expensive).
I understand that I can take the Piqually line straight to King's cross station. I'm assuming that from there I can purchase a train ticket to Edinburgh, or read something about taking a train to York and then to Edinburgh. There was a site that allowed reservations for a specific time in advance for 106 pounds for two people, but I'm afraid to buy in advance as I don't know how long it will take to get through customs and then to the station. As far as I know there is no direct train I can take from Heathrow.
Does anyone have advice on my best option and what the cost might be for two people?