Hey,
The video input got me aswell!! it was a tricky one!! i did first solder wires to the top of the connector and then onto the jack but that did not work. So what i did was take off the connector from the board and extend it with wires so it can be placed in a better location. Then you simply plug in the connector.
as for extending the gps....you will need 2 core cable. But to behonest i dont think you would need too as i get a good reception from it being stuck inside.
As for the switch look at what i did its very discrete and easily accessible
and lastly good luck too you