How far a drive is Hopewell Rocks from Shediac?
It will take you about an hours drive.
From Shediac, the Route 15 freeway takes you into downtown Moncton.
Route 114 goes to Hopewell Rocks. Once you get to the other side of the Petitcodiac River, it's about 22 miles. The road is paved two-lane undivided, but it passes through small towns, so you'll be lucky to maintain an average speed of 45 mph.
In Moncton itself, it would usually take you less time to take the direct route, negotiating the downtown streets and traffic lights, than to follow the Route 15 beltway all the way around the city.