One word of warning - try and avoid the first official day of Christmas decor and what not, which is usually the Friday of Veterans Day weekend. To put it as kindly as I can, all the influencer-blogger-people-pretending-to-be -celebrity-journalists crowd the parks to get merch and food and take all the staged pictures which causes ridiculous lines, congestion, and all around a bad experience for all. Go the day after.
But yes, decor should be up.