A travelling donor is one who is paid to travel to a chosen clinic to undergo treatment. I believe they usually collaborate with set clinics overseas as they don't usually meet the criteria set by clinics here in Australia.
QFG ethics committee require donors to undergo extensive testing including psych testing that can take some months - travelling donors don't usually allow for this extensive type of testing. I also found when I looked into it that the costs involved with travelling donors (even to overseas clinics) was quite prohibitive - I could do two DE cycles in South Africa for the cost of one with a travelling donor.
Warren will support you as you work with your chosen clinic overseas. We did two cycles in SA and both times he helped us with immune protocols, scans, medication support etc.
If you have any questions feel free to PM me.