Wide areas for picnicking, refreshing pools and these 3 sites quite close one to the other, so pick the one which is the closest (still I do prefer Ma'yan Harod)
Same as the other 2: try to avoid the weekends or the Jewish Feasts as the places then are absolutely overcrowded and then it is loud music, not always your style, correction, NEVER your style, and barbecues (or mangals) and shouting and pushing, and...well you got the picture.