Is this fleet existing or is it just an idea in you head? I a presume it is just an idea becuase surely you don't have several A310 sitting around in your back garden doing nothing?
Basing a fleet is one thing, looking for 'good cargo routes' is another. Trust me when I say what might be profitable in one direction, may seriously eat into your margins on the return sector. Rating structures in cargo are pretty cut throat on many routes..... some rating is just plain crazy.
It really does depend on your plan.
Can't say I am that clued up on the A310, what are the max payloads, and number of positions, ULD type?
Are the a/c full freighter config?