I would renew the chain and sprockets before setting off, and just maintain them carefully so I´d expect to get at least 30.000kms out of them. I wouldn´t change front fork seals unless they showed signs of giving up shortly. Would probably take them with me as spares.

I´d also take get wheel bearings front&back (and also have them and the steering head bearings checked before leaving), front sprocket, some extra master links, throttle- and clutch cable, bulbs, fuses and maybe clutch- & brake levers (unless you´ve got some knuckle guards installed, in which case I wouldnt bother), as well as brake & gearchange pedals. Oh, and the low-pressure fuel filter also.

My experience is with a 650, but they have a few things in common, even though the engines are quite different. The DL1000 may need throttle body balancing more often than the smaller version. We checked the Wee´s valve clearances and had the throttle bodies sync´d before leaving from Europe to Australia, and rode 35.000kms 2-up without having to do anything to the chain&sprockets (except lubricating and sometimes adjusting them of course!)..... not even the throttle body sync went bad, and when the valve clearances were checked after the trip, they hadnt changed at all. You need to take care of the air filter, though, if you want to avoid problems with these - as well as with a lot of other things of course!

We actually had a bag full of all sorts of spares, like spark plug caps, several relays, even one ignition coil, but I guess its rare to have a problem with these (and I can confirm this - we never needed to use any of our spares!).... and anyway I think in South America you may be able to find model specific or even original spares for big bikes better than you would in most parts of Asia.

edit. ok, I wouldnt get a clutch cable for the 1000, cos its hydraulic of course! And there was some problem with early model DL1000 clutch master cylinder, which I believe was fixed later on, but I dont remember when, so that might be worth checking out.