England to Barcelona by Motorbike. How Cheap (and Enjoyable) Can it Be?

How cheaply can motorcycle touring be done? I ride my 2010 Triumph Bonneville from Ipswich in England to Barcelona, Spain to find out. With the cheapest possible ferry ticket from Dover to Calais and toll roads (French Peages) turned off on Google Maps and wild camp for free in a tent (no official campsites), I attempt to find out