My sons thought the workload was heavier than that of AP Comp Sci A but lighter than any of the other APs they’ve taken.
Son 1: took course 1st semester of 10th grade. Grade in course A, score 4. His review consisted of 2 or 3 hour-long mandatory sessions.
Son 2: took course 2nd semester of 9th grade. Grade in course A, score 5. Although his class covered the material in less time than his brother’s not having a four month gap between the course and exam helped.
If you are strong in history you should do fine. Take advantage of any study sessions your school offers. You teacher may also recommend online resources.