VGA is a high resolution video signal and requires a properly designed cable to carry it over a long distance. Many short VGA work over a length of 1,5 m and do not comply with the transmission standards for long distances. For long distance transmission, a 75 ohm coax cable is needed for each signals. This type of cable is usually made to order an very expensive. Standard cables over 30 m are rare.
I think your best option is to use a TCP/IP network and use VNC (Remote Desktop).