Well, in the East Coast of Canada we have the L'Anse aux Meadows archaeological site in Newfoundland. It dates to around the year 1000. Unfortunately, I haven't ever seen any written records of raids from the native communities of Eastern Canada since the native groups there did not keep written records; but enough vikings were coming that a settlement was created. This is definitely the furthest point of viking contact away from Scandinavia that I've ever seen that has been widely accepted by historians and archaeologists. We also have (so far speculative) sites in Northern Canada in the Arctic region as well such as Nanook and Nunguvik; there is evidence of Norse-Native American trade networks and it is likely that raiding occurred as well. This is all more than 500 years before Columbus sailed.

Parks Canada has a brief leaflet on the site: http://www.pc.gc.ca/eng/lhn-nhs/nl/meadows/visit/ac.aspx

The furthest they tried from the Atlantic was Rome. It´s unclear if they actually found it, or some nearby cities. It was not a very succesful tour, mostly because a fleet attacked them near Gibraltar on their way back. Less then half of the boats returned. I dont have the sources at hand, but these were probably organized from Normandy.

The Rus, based in todays Ukraine attempted some raiding in Byzantine (Istanbul). If I remember correctly they did not attack the heart of the city, which was behind walls, but only raided in the outskirts of the city.

Am travelling, dont have the sources at hand. I think both of them I read in "The Viking world", a collection of essays by academics. Stefan Brink is the Editor.