There are kits you can get from Graybar, and other telecomm suppliers, that are designed to help with this situation. Ask about the Greenlee 'Portable Blower Fishing System.' You might also google for 'Conduit Pistons.'
It's worth noting that these kits draw their inspiration from the pneumatic message-capsule delivery systems seen in Sam's Club, Costco, and other large buildings. Such systems have, if I recall my history correctly, been around since the latter part of the 19th century.
Direct-burial cable would certainly be an easier route, but you should check your local electrical codes. It may be that you would need to run power in a separate conduit (assuming that it's 115VAC). If it's low-voltage, this may not be an issue.
Happy tweaking.