November is not the best time but not bad. Great Wall is huge and long, resting at many provinces in China. In tianjin, you can visit Huangyaguan Great Wall. To get to there, you can first take long-distance bus from Tianjin Hebei Coach Station to Jixian County (CNY25 per head, a trip of 2 to 2.5 hours). And then you can take van from Dule Temple of Jixian to Huangyaguan Great Wall (CNY7 per head, a trip of half an hour). Back from Huangyaguan to Jixian, you can just take bus in front of the entrance to Huangyaguan.
Wish you a nice trip！