There seems to be hundreds of km of gravel roads in the area, and looking at the Denzel scale*, some sound quite difficult, 3-4 and 4, or even 5!!!
I guess finding a campsite is favourite, Camping Municipal St Jacques for example, then ride out each day without luggage on the bikes.
This could be a very interesting ride....
* The Denzel scale, degrees of difficulty:-
Translated by Google.
Difficulty
The levels of difficulty (SG) refers to the famous alpine roads Denzel scale.
SG Information on points related to the difficult places of the most frequently used driving. The classification depends on the maximum difficulty occurring, it is no average formed. Thus, when a track on which a frame (not too short) section 4 SG, SG 2 but otherwise, it is classified as SG 4 typically. This is to avoid nasty surprises halfway, but also that some of the routes specified SG is higher than the "perceived" leads.
Since the Denzel-scale focused mainly on two-lane vehicles, here the importance of difficulty in keywords and comments for motorcyclists:
SG 1 - Very easy route
• Road: normal thickness (> = 6 m)
• Decking / state: continuous smooth asphalt or concrete
• Border security: present throughout
• Routing: no strongly curved corners, no or very few, widely diversified Return
• slopes: max. 9%
• Requirements: for beginners
• Motorcycle classes: suitable for all machine
SG 2 - distance without significant requirements
• Road: two lanes
• Decking / Condition: mostly asphalt, possibly worse condition
• Border security: for the most part available
• Route: developed sufficiently wide sweeping with little slope in the inserts
• Rise: Max. 15%
• Requirements: Average, suitable for beginners with driving experience
• Motorcycle classes: suitable for all machine
SG 3 - route requires driving experience in the mountains
• Road: mostly two-lane, single lane with passing places in sections
• Coating: partially or completely missing asphalt or poor condition
• Border security: missing to a large extent
• Route: many, strongly curved bends, tight corners with greater slope
• Rise: over longer distances more than 15%
• Requirements: driving practice required on mountain roads
• Motorcycle classes and touring bikes, sports limited
SG 4 - Difficult and sometimes dangerous route, requires above average driving skills
• Road: mostly single track, a few passing places
• Decking / Condition: inhomogeneous, hardly entertained, sometimes coarse gravel, heavily washed or driven roadway may have Side slope is slippery when wet (mud, grass, loamy subsoil), has any bottlenecks by landslide and / or impassable on fords
• Edge protection: up to a few dangerous places no edge protection
• Route: very narrow, not sweeping developed
• Slope: Slopes above 20% or 15% at altitudes above 2000 m
• Requirements: above-average driving skills required!
• Motorcycle Classes: enduro, touring restricted. Possibly. sufficient ground clearance needed tires with a rough profile of advantage
SG 5 - Extremely difficult and dangerous route, driving at your own risk and never alone!
• Road: hardly any, on the border area
• Decking / state: on the edge of decay, rough gravel, bare rock, sand, mud, dangerous narrow, high rockfall, severe erosion, land-slide and side slope; fords that can not be passable at times.
• Border security: no
• Route: not always visible, no or very dilapidated expansion
• Rise: extreme inclines, switchbacks and even in altitudes above 2000 m
• Requirements: terrain reserved for professionals with appropriate machines!
• Motorcycle Classes: only light enduro / motocross machines, with strong restrictions may also touring bikes. Long-travel suspension, high ground clearance and track custom tires required!
The closest it gets is Col de Tende.
its a walk in the park for you. 
I'd be on an 1150 GS and another chap on an 1190 Adventure.
