Wind speed, as broadcast, is always less than actual wind on the lake.
As suggested, 12-MPH is a good threshold, especially as that speed is showing a few whitecaps. For sailing, that's a speed that's ideal!
You can still sail in a wind at 5-MPH, when no wind appears--y'know, "when it's calm".
For docking in a breeze, there's a modified boat hook available that allows a single boater to drop a loop over a piling or upright.
As oversized boats are ruining Winnipesaukee boating and eroding shorelines, I'm loathe to suggest a larger boat; however, 'toons are especially Winnipesaukee-friendly boats.
Also, I see many of the larger 'toons managing heavy chop very well. On another lake, a neighbor had a passenger fall off their smaller pontoon.
Fortunately, it occurred in a shallow canal. I recall the brand being an "Aqua-Patio" pontoon boat.