Maybe already you will know but here some suggestions:
I installed ChunkVNC and like the way the repeater works.
But would like to have:
1) Possibility to install, from the compiled version and on the remote computer, the server (as service) with fixed access code en password.
2) A central management application in where all computer can be managed in groups (sites)
3) Copy and paste from and too the remote site
After install the user will see the access code and must be reminded to write that down, this code can be told or send to the helper
This code will be stored in the central manager and on the server where the repeater is running in case of rebuilding the helper desktop computer.
The central manager running on the helpers desktop PC fetch all access code from the server without password, this password only can be added on the helpdesk PC.
The server and the helpdesk PC with the management console must be able to update, maintain (synchronize) on both side the "phone-book" with access code.