Doing a run alng the south coast of the island is a potentially beautiful holiday if the the timing is right. Summer is short in Newfoundland - last week in July and first week in august is the time everyone seems to try to take their holidays up here to get the best chance of weather.
Fog is definitely a consideration, anytime there is a southerly component to the wind, there is a good chance of fog, dense fog. Radars are valuable devises. Invest in a pilot book for the areas you intend to travel - there are dozens of great anchorages and some deep fjords (white bear bay for example).
Watch the weather carefully gales are common.
There is a nice yacht club in conception bay -RNYC, actually two there is another in Holyrood, about ten miles further in the bay.
I think you will enjoy the trip, but you should ensure that you are prepared for the above.