Joe Biden, with daughter Ashley and son Beau, arrives in Lexington, Ky. on Air Force Two. (Pablo Martinez/Associated Press)

DANVILLE, Ky. -- Vice President Joe Biden and House Budget Committee Chairman Paul Ryan (R-Wis.) have arrived at Centre College, the site of their much-anticipated face-off in Thursday night's vice presidential debate.

But the two aren't likely to cross paths ahead of their first and only debate, aides said.

Biden, who arrived by motorcade at the debate site shortly before 2 p.m. Thursday, took a brief private walk-through of the venue and is expected to spend the remainder of the afternoon and evening at the private residence of some local supporters, together with family, friends and some aides, a campaign official said.

Ryan, who arrived in Kentucky early Wednesday evening and spent the night at a hotel in nearby Lexington, is spending the afternoon onsite at the college, according to a campaign aide. He took his private walk-through of the debate site earlier Thursday.

Biden's preparation has included three days of "debate camp" at a hotel in Wilmington, Del., with nights spent at home with his family there.

His routine consisted of morning policy sessions, afternoon mock debates against Ryan stand-in Rep. Chris Van Hollen (D-Md.) and a further briefing in the evening. Biden communications director Shailagh Murray played the role of moderator Martha Raddatz of ABC, a campaign official said.

For Ryan, the lead-up to the debate included three days of "debate camp" in central Virginia as well as two days this week in St. Petersburg, Fla.

He has held multiple mock debates against former solicitor general Ted Olson, his Biden stand-in; former Massachusetts lieutenant governor Kerry Healey has served as moderator.

The two candidates have been surrounded by aides as well as family members in recent days. Among those at Biden's debate sessions have been his former chief of staff, Ted Kaufman, who was appointed to Biden's Senate seat in 2008 and served for two years; National Security Adviser Mike Donilon and chief of staff Ron Klain, as well as Obama chief strategist David Axelrod.

Those joining Ryan at his recent sessions included foreign policy adviser Dan Senor and senior Romney adviser Russ Schriefer, as well as his regular traveling aides.

Both candidates also spent their night before the debate eating dinner with family. For Ryan, that dinner was at the hotel in Lexington; for Biden, it was in Wilmington, where he and relatives dined on homemade lasagna that Biden's grandson, Hunter, helped to bake, according to an aide.

Thursday, Ryan has been spending time with his family, studying his policy binders and exercising; he ate a tuna salad sandwich for lunch and will eat salmon with rice for dinner, an aide said.