A candidate in isolation: Inside Biden's cloistered campaign

For a team that employed a relatively skeletal digital operation throughout the primaries, the sudden shift toward online campaigning has been abrupt. At times, Mr. Biden has appeared out of his comfort zone and he continues to express a kind of chuckling disbelief that his basement has become a makeshift studio. Advisers acknowledge that they have considerable catching up to do on sites like Facebook and YouTube.

Mr. Biden is also facing pressure from donors to ramp up his at-home fund-raising activities, and from leaders in the states who want to see him beaming more often into key battlegrounds. To that end, he has recently conducted a series of interviews with local television stations in markets like Detroit and Pittsburgh, with more planned.

But Mr. Biden is burrowing in for the long haul, telling donors this month he did not anticipate holding traditional public events anytime soon.