Only a few can be so isolated (8)
I believe the answer is:
lonesome
'isolated' is the definition.
(I've seen this before)
'only a few' is the wordplay.
'only' becomes 'lone' (synonyms).
'a few' becomes 'some' (both can mean a small amount of something).
'lone'+'some'='LONESOME'
'can be so' acts as a link.
(Other definitions for lonesome that I've seen before include "Solitary (mainly US)" , "On one's own" , "Sad and lonely" , "Trail of the - Pine (Laurel and Hardy in Way Out West)" , "Solitary (chiefly US)" .)