I have been thinking a 2x8 would be good on the road. 11-32 is possible with a Shimano CS-M950 Ti in pretty light weight. Light front is doable in say 34~48 and it should give enough overlap that in many cases you can just stay on one ring up front for most of the way
Many x9 rears have nearly the same spread. It depends on what your bottom gear needs to be for your worst climb ?? And what your top speed needs to be for your fastest raod sections ...