Oh, I've watched OLTL for years!
Here's the Ralston family tree:
http://www.soapcentral.com/oltl/ftrees/ralston.phpYancey Ralston was rumored to be Bo's father. When the latter went to Louisiana to learn more about his supposed roots, he fell for Euphemia's daughter Delila and vice versa, but they didn't act on it because they supposedly were cousins. Euphemia wanted to get back the family fortune (though she must've married into the family), so she, her daughter Delila, and her nephew Drew moved to Llanview. The letter you mentioned that Euphemia was trying to get her hands on (written by Twyla Ralston) said that Yancey was sterile, so of course he couldn't have been Bo's dad. Asa knew Bo was really a Buchanan, but he kept it a secret cuz he had set his own sights on Delila. By the time Bo found out the truth, Delila and Asa were already married, so Bo slept with Becky Lee and (unbeknownst to him) she became pregnant.
Then Asa faked his own death (<yawn>) so Delila and Bo had an affair, and when Asa showed up (I think at his own funeral), Delila realized she'd been played and dumped Asa for Bo. Delila found out that Becky Lee was preggers with Bo's baby, so out of insecurity she kept it to herself and also faked her own pregnancy even though it wasn't at all possible. In the meantime, Becky Lee was supposed to marry Drew but he was murdered. Asa found out she was going to have his grandson so he talked Becky Lee into marrying him. BL eventually told Bo the truth and when he found out that Delila knew all along, he dumped her. I can't remember what led to Euphemia's exit, sorry.
Vicki (Lord), btw, married Asa's other son Clint when she got out of that jail.
Thanks for jogging my memory, Gothick! Aren't we glad we were spared these types of storylines on DS? Til 1841 PT, that is.