I'm planning to do the GR20 - regarded as Europe's toughest trek - back to back with Selvaggio Blu - regarded as Italy's toughest trek/climb/repel - in June and July. The GR20 takes between 10 and 14 days, and Selvaggio Blu around 5-7 days to complete. Travelling light (bivvying, mountain huts and sleeping bag), and keeping costs down is the order of the day for both trips, in particular Selvaggio Blu, which involves some climbing and repelling along the stunning coastal route, supported by local operators who can stash water and food along the route, and provide boat pick ups. The adventure could start in either Corsica or Sardinia - I'm easy. There are 3 or 4 ferries from mainland Italy to Sardinia, and a couple of ferries from Nice or Toulon to Calvi, Corsica, and a ferry between the two islands. If you still have time and energy I'm thinking of heading over to Naples and then Stromboli to check out one of Europe's most active and spectacular volcanoes. Feel free to join me for part or all of the trip: firstname.lastname@example.org"