Gillingham's win cemented their place at the top of League Two.
The former AFC Wimbledon striker's double takes his league tally for the season to six, his first coming after five minutes from the penalty spot after he was bundled over from behind by Tom Parkes, who was lucky to stay on the pitch as the last man.
Ten minutes later the forward claimed a second - Charlie Lee's long throw was hurled into the area and Kedwell's front-post flick-on from a tight angle looped over a helpless Sam Walker.
It was all Gills and the third came on the stroke of half-time as a diving Lee got his head to Charlie Allen's right-side corner to power in.
Wayne Brown and Oliver Norburn eventually tested Stuart Nelson after the break for Rovers, but the game was wrapped up as substitutes Myles Weston and Chris Whelpdale combined, the latter nodding in an inch-perfect cross.