Travel recommendations for 2-3 weeks in June

My boyfriend and I are planning a trip this June for 2-3 weeks and looking for suggestions of where to go. Preferably somewhere there won’t be huge crowds and where the weather will be relatively good that time of year (especially places where June would be the ideal time of year to visit). Open to multi-stop trips (by train, bus, car, or ferry) and hidden gem destinations. Thank you!