We went in 2013 (NL and Lab) and will go again this year. We should arrive in NL mid May sometime. YES, we know the weather will be cold and possible freezing temps if we hit it wrong. So...we were home (thru labrador) by the end of june last time...40+ days total.
Best time mid to late June if you want the place to yourself...almost. Otherwise, later = warmer. We mostly boondock with occasional campground and some provincial parks will be open early.
Donna