The Vikings were looking to bounce back to the top flight at the first attempt but had to answer to the pace and skill of the Rovers side, who have taken their club to Super League for the first time.
Mick Cassidy sent Gavin Dodd over the line for the Vikings’ first touch down of the game, but the Robins were not finished, a second try from Goddard giving them a 22-4 interval lead.
Pat Weisner touched down soon after the restart to continue the Hull’s dominance of the game, but a score from Bob Beswick kept Widnes in touching distance.
Murrell kicked a drop goal for Rovers before Damien Blanch grabbed another score for the Vikings, who now had a slim chance of stealing the win.
However, Hull were too strong for their opponents, and the game was over as a contest by the time Gareth Morton kicked a penalty goal on the final hooter.
Morgan said: “I think we saw the determination that has driven this team all year. They've worked very hard for 11 months and they've become very close.
"I'm very privileged to be able to coach a bunch of players like this and go down in history by getting Hull Kingston Rovers into Super League.
"I thought the first 40 minutes was the best we've played all year. We kicked exceptionally well, we had a great attitude defensively and our kick-chase was spot on."
Widnes coach Steve McCormack, who has lost the last two Grand Finals at the reigns of Whitehaven, said that this was the worst feeling, but congratulated his players for their attempts to get back into the game.
“This feeling is worse than ever. We knew what Hull KR would do. They started a lot quicker” said McCormack.
"They looked quicker around the play-the-balls and their kick-chase was outstanding. Justin deserves a big rap. They've been fantastic all year.
"But I'm very proud of the way my team responded when they could have crumbled. We were just left with too much to do."