In the meantime, he would try to find out more about Voldemort, if only because "know your enemy" was a universally sound advice.
He initially wanted to go to the village of Little Hangleton and see what he could find out about the Riddle family. Voldemort had gathered his Death Eaters in Riddle Manor on many occasions. He didn't know of any Wizarding family called Riddle, and he suspected the family had changed its name at some point in history, to escape retribution or maybe a blood feud. He knew the Gaunts used to live nearby, and he'd have asked them about the matter if they hadn't all been murdered years before.
He'd have gone snooping around, to ask the locals if nothing else, but Marius and Leona had talked him out of it, saying that it would be just his luck for a Death Eater to be there and recognize him.
But then Ted had shown up, said he'd had his London "acquaintances" check the history of the Riddle family, and dropped a literal bomb: Riddle was not a wizarding family. It had always been a normal, albeit rather wealthy, family of muggles in the area. The last known Riddle, Tom, had died in 1943. Further inquiries into the name Riddle revealed that a Tom Marvolo Riddle later grew up in an orphanage and then "attended a school for the gifted" in Scotland between 1938-1945, after which he seemed to disappear from the grid.
Regulus had stared at the papers and Ted, then Ted and the papers, in shock for at least ten minutes. The Dark Lord, who spouted pureblood propaganda like it was divine nectar, was the half-blood bastard of a muggle and the near-squib Merope Gaunt, who'd died right after dumping her son at a dreary muggle orphanage.
The Scion of the House of Black almost felt sorry for the Death Eaters. Almost. He wondered how the purebloods would take it if they learned, especially since it would disprove the whole idea of power being tied to blood purity, with Voldermort being a half-blood squibspawn and everything. At least they had an excuse in that Voldemort had modified the Riddle Manor enough that it wasn't so obviously muggle anymore.