masmith, I do that route quite often - doing it now, as it happens!

Best route (largely followed by all the 'pioneers', like Amy Johnson and Francis Chichester) is probably Luqa (Malta) - Iraklion (Crete) - Tel Aviv - Kuwait - Muscat - Karachi - Delhi - Calcutta - Rangoon (Yangon) - Singapore - Djakarta - Suribaya - Dili (East Timor) - Darwin.
But that's with the aeroplane I'm using at the moment - Hurricane Mark II, with a range of 500 miles (and I can get 700 out of it with coarse pitch, lean mixture, and some help from the wind). Being a trainer, the Chipmunk will only have a very short range (about 250 miles?) so you'll have to find other places to land and refuel in between.
If range is a problem you could try putting on bigger fuel tanks - which is what the real long-distance people did. Find the aircraft.cfg file, back it up, then look for the fuel section, type in bigger fuel figures, and re-save it. With luck, if you're reasonable (maybe just double the figures?) it won't affect the flying performance (except that it will maybe feel 'heavier' on takeoff). If it spoils it, put the backed-up file back in.
Good luck with the trip, hope you make it!