The worst area in Summer is Northbound into Ogunquit. Half an hour to go one mile is common.
X 2. Even more than 30 minutes is not unusual. Once Memorial Day hits we don't venture up there until after Labor Day unless we leave here late afternoon or go on a weekday. We have no use for Rt 1 during peak season-too busy and not much for scenic views. However, driving the 5er through there shouldn't be a problem.
As an FYI, do NOT take the fifth wheel down to Perkin's Cove should you decide to venture off Rt. 1 in Ogunquit. You will not fit for one and I believe there is a sign that says you cannot enter that area.