Stay very close to shore in a Hunter. I used to have access to a Hunter 25 and took it in the ocean a few times. The boat just really wasn't built for it. In bigger conditions it doesn't handle well at all, almost to the point of being unsafe. To me this comes down to a couple things: a slow hull, and an underpowered rig. Add big waves and making headway or tacking is very difficult, especially in a decent chop. Running the motor you will usually be ok, but it still depends on the conditions. In the same conditions a J/24 is much more fun and it's raceable.
Sorry but the J-24 is hardly a safer boat than a hunter. They have serious ultimate stability issues, and can downflood THROUGH THE COMPANIONWAY in a knockdown, even if you fix that pesky cockpit locker issue they have.
What kind of Hunter 25, Cherubini or the newer ones? I have a 1982 Cherubini Hunter 25, and although I certainly wouldn't even dream of circumnavigating in it, it is a fairly well built vessel. The deck/hull joint is solid and reinforced with 5/16" bolts along the toe rail. The cabin floor has a "grid" over the keel, spreading the loads properly (many boats of this size do not have a grid at all). The companionway hatch would be a weakness in true ocean conditions (too big, difficult to secure, nowhere near watertight) and is also a weakness in a knockdown but will still keep 99% of the water out.
Instead of worrying about the motor, worry about a proper jiffy reefing system for the main and worry about having a small jib, something about half the size of a working jib, that can be easily put up for when the wind picks up. The boat is not underpowered at all, when the wind gusts at 20 you better have two reefs in the main and a working jib will almost be too much sail.
As far as chop/swells/etc, here's a link to a video of my boat making good progress in some relatively heavy stuff right off Coney Island: