Lucas wrote an extensive time-line detailing the life of Indiana Jones, assembling the elements for about 70 episodes, starting in 1905 and leading all the way up to the feature films. Each outline included the place, date and the historical persons Indy would meet in that episode, and would then be turned over to one of the series writers. When the series came to an end about 31 of the 70 stories had been filmed. Had the series been renewed for a third season, Young Indy would have been introduced to younger versions of characters from Raiders of the Lost Ark: Abner Ravenwood ("Jerusalem, June 1909") and René Belloq ("Honduras, December 1920"). Other episodes would have filled in the blanks between existing ones ("Le Havre, June 1916", "Berlin, Late August, 1916"), and there would even have been some adventures starring a five-year-old Indy (including "Princeton, May 1905").
Young Indiana Jones was not perfect but I thought the series had untapped potential. In fact it was pretty much canceled before it had the time to become interesting. I would have loved to see Abner, Belloq, and other movie characters in the third and fourth seasons.