There are 2 parts to these directions. First, how to get to the ferry dock at Millhaven. Second, how to get from the ferry dock on the Island to Poplar Dell.
Millhaven is on the northern shore of Lake Ontario about 20 km west of Kingston. The major highway that gets you pretty close is Canada’s Route 401, which is the major east-west highway in this part of Canada. Millhaven’s exit is km 593, also known as county road #4. Go south (towards the Lake, obviously) about 10 km, where the road dead ends into route 33, at the Lake’s shoreline. Turn right (west) on route 33 and go several hundred meters, looking for the Amherst Island Ferry sign. Turn left into the parking area and wait for the loading to begin.
After the short ride to Amherst, follow the ferrymen’s instructions to drive off the ferry. You’ll find yourself in the main town, Stella. Drive straight ahead several hundred meters to the 4-way stop. This is Front Road, but I don’t think there’s a sign to that effect. Anyway, turn left and drive about 2 km, to 3190 Front Road. The house numbers are in meters from the foot of the Island, so you can always tell how far to go by looking at the green “911” signs. If you start seeing numbers less than 3190, you’ve gone too far. There’s 3 or so parking spaces in front of the main house, feel free to park there (or anywhere else, if need be, there’s lots of open space).
Remember you are trying to get to Millhaven to get the ferry, which leaves on the half-hour. From the west (i.e. Toronto) you are one hour from Millhaven when you pass the big red apple at km 497. From the east/US, you are one hour from Millhaven when you clear Canadian customs. From the east/Canada, the Ganonoque casino (where the Thousand Island parkway joins the 401) is 45 minutes away. Other more approximate times include: Windsor – 6 hours; Toronto – 2.5 hours; Ottawa – 2.5 hours; Montreal – 3 hours.