The Early Adventures continued telling stories from the first two Doctors that The Companion Chronicles began, although producer David Richardson described the series as having a format closer to that of The Lost Stories "except here we have pushed the format to make these productions sound as much as possible like full cast drama".
In producing The Early Adventures, Richardson also stated that it was intended for each story to feel like the soundtrack to a missing episode of the TV series, following the final audio release of an incomplete BBC serial, The Reign of Terror, in 2006. The first releases aimed to replicate this by having all actors speak in RP (Received Pronunciation) as opposed to regional accents and the use of sparing narration to explain actions hard to portray without visuals. (VOR 67)
The stories were performed with two of the original cast along with a cast sized similarly to the Doctor Who monthly range. The two original cast members performed and narrated characters such as the Doctor and other companions.
Series three saw the return of the First Doctor. For the first two stories, the role of Barbara Wright was recast, as Jacqueline Hill was deceased. She was now voiced by Jemma Powell, who had previously played Hill in An Adventure in Space and Time. Additionally, the first story featured Ian and Susan, while the second featured Ian and Vicki. Like the first series, the third story featured Vicki and Steven, while the fourth featured Steven and Sara.
Series five took a different approach to the previous four. Rather than telling four stories with a revolving cast of companions, all stories featured the First Doctor, Vicki and Steven in four chronologically-consecutive adventures. The plan for this series was to "do a season of 1960s Doctor Who."