But while Mrs. Clinton focuses her time in the state, she has a number of supporters — including President Obama — who can campaign on her behalf elsewhere.
Mr. Trump is closer to a one-man show, relying mostly on his family and his running mate, Gov. Mike Pence of Indiana, to fan out across the country.
Here’s what to watch for on Thursday.
Will Melania Trump soften her husband’s image?
Ms. Trump, who has studiously avoided the campaign trail, is making her first solo appearance. She will appear in suburban Philadelphia, with a speech tailored to women and mothers about what a President Trump might do for their lives.
In her few media interviews, Ms. Trump, a former model, has had a softening effect on her husband’s hammer-blunt approach. She told Anderson Cooper on CNN recently that she was appalled by remarks Mr. Trump made about women that emerged last month on an 11-year-old “Access Hollywood” recording, but she portrayed him as merely boisterous.
Ms. Trump will use what little time is left to improve his dismal standing with female voters.
Will the president continue trying to bait Mr. Trump?
Mr. Obama savaged and belittled Mr. Trump in North Carolina as he hit the campaign trail for Mrs. Clinton on Wednesday.
The president is able to taunt Mr. Trump in a way few others can, and he may be back at it in Jacksonville, Fla., on Thursday. Mr. Trump, as it happens, will also campaign there.
Mr. Obama’s criticism of the F.B.I. director, James B. Comey, on Wednesday over the investigation into Mrs. Clinton’s private email server may provoke a reaction from Mr. Trump.
Can Mr. Trump continue to resist?
As he took the stage at his final rally in Florida on Wednesday night, Mr. Trump spoke out loud to himself.
“Stay on point, Donald; stay on point,” he said. “Nice and easy, Donald.”
It’s unusual for a candidate to state such stage directions out loud. But though Mr. Trump has reliably erupted at insults throughout the campaign, he now seems to be doing his best not to respond.
Can Mrs. Clinton break through?
Democrats have projected a war-room-style message since last Friday, when Mr. Comey sent a letter to Congress informing members of the F.B.I.’s renewed interest in Mrs. Clinton’s email server. Democrats attacked Mr. Comey and called the developments unusual.
Mrs. Clinton has tried to refocus her attention on Mr. Trump. But her message is tactical and demographics-based, seeking to appeal to African-Americans, Hispanics and women.
Mrs. Clinton is missing a broader closing argument.
Can Bernie Sanders help?
Mr. Sanders will be with Mrs. Clinton in North Carolina on Thursday, resuming events on her behalf that have been focused in states with large populations of white working-class voters.
At a rally on Wednesday night, Mr. Trump maintained that Mr. Sanders would soon withdraw his support for Mrs. Clinton because of lingering ill feelings from their primary fight.
Mr. Sanders’s schedule, which includes Clinton events this weekend in Iowa, suggests otherwise.
What else does WikiLeaks have in store?
The damage from the disclosures of hacked and stolen emails from the account of John D. Podesta, Mrs. Clinton’s campaign chairman, has been limited primarily to negative headlines.
The founder of WikiLeaks, Julian Assange, has repeatedly teased that he will continue to drop new information. Mr. Trump said on Wednesday that he thought more damaging information would emerge this week — and that he would talk about it once it did.