Elizabeth Stoddard's Secret? And Early Dark Shadows Questions

[McTrooper]

I've watched a few clips from the earlier episodes and I wonder . . What kept Elizabeth from leaving Collinwood  for over 18 years?  What was her secret? 

Also . . did Burk Devilin really do much?  What was his real reason for coming to town?  What happened to him?

I remember going through the summaries from someone's homepage several years ago, but I don't remember the answer to my questions or if they were answered. 
Also I'm not sure if Elizabeth's Secret is related to the Leviathan story line in which Paul came back.  Because apparently Liz started isolating herself in Collinwood after
Paul left. 

Was there any behind the scenes story line changes?  You know something was going to turn out this way but it got changed.

[Miss_Winthrop]

[spoiler]Liz thought that she had killed Paul by hitting him over the head with a fire poker.  Paul's friend Jason McGuire helped Liz cover up the crime by burying Paul in the basement or so she thought.  That was her guilty secret for 18 years and kept her tied to the estate. Devlin came back to town to make Roger Collins and the rest of the Collinses it seems, pay for his being falsely accused of running a man down on the road while he (Devlin) was driving drunk after a big night I presume at the Blue Whale with Roger and Laura.  There were problems between Roger and Burke because they were both vying for the attention of Laura which added tension to the friendship between the three of them.[/spoiler]

[GooberCollins]

[spoiler]Burke was also apparently killed in a plane crash just before 1795. David predicted this event, and Barnabas was happy because it saved him the trouble of getting his hands dirty by killing Burke himself.[/spoiler]

[McTrooper]

Thank you, both of you.  That satisfies most of my questions thought I do have a few more now. 
[spoiler]Uhm . . GooberCollins when was that plane crash?  Also . . so Barnabas meet Burk.  Why did he want to kill him?  Did Burk actually make Rodger or anyone pay (i.e. did he do any damage to the family)?  [/spoiler]

[GooberCollins]

[spoiler]As I said, the plane crash occurred a little bit before the beginning of the 1795 storyline. Barnabas wanted to kill Burke because he fell in love with Vicki (and probably planned to groom her into Josette #2, as he tried to do with Maggie), and Burke was a major rival for her affections. I believe he thoroughly trashed Roger's reputation and endangered the cannery's prosperity a few times, but nothing much else.[/spoiler]