long time ago,i crossed all of europe in a 2cv..:-),amazing journey i can tell you that.the preparations we made back then,involved adding a second gastank with electronic switch inside,the panel behind the door where the gastank is,you have one on the other side too :-),perfect fit for an aditional gastank without losing inside space. we changed the springs in order to put more load in it.we added an extra airfan in the motorcompartiment for extra cooling.
we took the most avarage spare parts with us,like spark plugs,tyres,oil,jointpaper,so you can make your own joints if needed.
the only problem we encountered back then was breaks getting overheated in mountain area's,probably due to the heavy load we had with us..
terence kennedy a well known 2cv traveller by 2cv lovers,travelled 74 country's with his 2cv ..:-),and have written a book about it,mayby its a good thing to read it.its called 'a nonsense of direction' isbn.0-9517886-0-4.
hope you enjoy your journey.