Start in Lisbon, on the western edge of Europe, and head east... towards China. Or start in Capetown and head north towards the Meditteranean. Or south from Kirkennes.... East from Vladivostok... you get the idea.
Or start in Istanbul, between Europe and Asia, and head in any direction you choose.
Well, since you're just about to start, it really helps if you know something about which hotels to stay in to and which not. You could visit -snip- to check out these hotels and see which places are appropriate for you and your friend.
[ Edit: Sorry, no promos please. ]