Just to share my experience. From my experience, I have to limit the query timeband when accessing the API. There is not a fixed duration for the timeband as some stations are busier while some are less, which means that the amount of information related to each station is very different.
Also, the from_loc and to_loc key do not represent the originating and terminating station. For example, if I set the Woking (WOK) and Waterloo (WAT) as the values for the keys, I can obtain all the RIDs related to this route. With the RIDs, I can then use the serviceDetails call to get all information related to the RID, from originating to terminating station.