Rest assured that you can indeed enter the airways. I've done it several times. I haven't flown one in several months, so I can't give you exact details.
From te FPLN page, I believe you move the FMS cursor to the space BELOW the waypoint on the airway then go MENU>LD AIRWAYS.
Unfortunately, it's not entirely intuitive. I'd say check the manual in the en-route section. It is there.
FYI, there's no such thing as a VFR G1000. The unit is IFR capable and certified, and will put the avionics on all but a few modern jets to shame.