Sen. Rob Portman broke away from his 17-year-old daughter’s tour of his alma mater, Dartmouth College, to venture an hour south of here Saturday to trumpet the virtues of Mitt Romney.

Louisiana Gov. Bobby Jindal and former Minnesota governor Tim Pawlenty spent Thursday and Friday shadowing President Obama as he traveled through Ohio and Pennsylvania, taking turns tearing into the president as they stumped in front of “Romney Victory” banners.

Sen. Marco Rubio (Fla.) is jetting to Boston this week to raise money for Romney in the candidate’s home town, and Rep. Paul Ryan (Wis.) is headlining a Romney fundraiser in Illinois. And two weeks ago, when Romney campaigned in New Jersey, it was Gov. Chris Christie who gave the presumptive nominee some juice and bragged about having endorsed him earlier than most other Republican governors.

With the prospective vice presidential candidates fanning out as campaign-trail surrogates, Romney and his closest counselors have entered the final stages of selecting the ultimate surrogate — a running mate.

There are seven weeks remaining until the Republican National Convention in Tampa, and Romney has a few important strategic decisions to make before then: not only who to name as a vice presidential nominee, but also when and how to do so.

Will Romney follow the precedent of both parties in 2008 by waiting until a few days before the start of his convention to announce his pick? Or will he elect to name a running mate sooner to effectively double the Republicans’ ability to raise money and campaign against an incumbent president and vice president?

And if Romney goes the early route, will he make the announcement over the next 21 / 2 weeks before he departs for ­Europe to begin a foreign trip? Or will he wait until he returns from overseas in early August, when the campaign will be competing against the London Olympics for media attention?

Romney campaign officials would not comment on the confidential vice presidential selection process but said nothing has been determined.

“No decisions have been made about decisions,” one adviser said.

When Romney was asked by CBS News last week when he might announce his choice, he said, “I can’t tell you that. I have an idea in mind, but that’s something I’m keeping close with my team.”

Romney said he would make the decision with Beth Myers, his longtime senior adviser, who is leading his search. Myers, campaign manager Matt Rhoades and chief strategist Stuart Stevens were seen meeting with Mitt and Ann Romney on Tuesday during their family vacation in Wolfeboro, N.H.

In the CBS interview, Ann Romney left little doubt that she, too, will have a say. She said she wants a running mate who is “competent” and “capable” and who has “the same personality type” as her husband. Asked whether she thinks her husband should nominate a woman, she said, “We’ve been looking at that, and I’d love that option as well.”

Ann Romney did not name names, but one woman who has generated considerable buzz recently within Romney’s campaign is former secretary of state Condoleezza Rice. At a private retreat for Romney’s top donors in Utah, Rice delivered a ­luncheon speech that garnered two standing ovations and left many fundraisers openly touting her for the ticket.

Other prospective candidates also appeared in Utah, including Portman, a former official in President George W. Bush’s Cabinet from the critical battleground state of Ohio. Portman will be in Boston on Monday holding several events on Romney’s behalf, including a fundraiser. But ­although Portman’s trip to New Hampshire overlapped with Romney’s vacation, he told ­reporters he had “no plans” to visit with the former governor.

Romney said last month that he is thoroughly vetting Rubio, and others believed to be on that list include Pawlenty, Jindal, Ryan, Christie and Sen. John Thune (S.D.), another guest at the Utah retreat.

At Romney headquarters in Boston, top staffers are readying for an announcement. A senior staff for the eventual nominee is beginning to be assembled, while the digital team is planning a swift rollout designed to maximize engagement and fundraising from supporters online. The goal, advisers said, is to have an infrastructure ready once Romney makes the decision.

As they eye the calendar, Romney’s advisers said they are weighing the pros and cons of timing.

Steve Duprey, who traveled in 2008 with Republican nominee John McCain as a senior adviser, said the Romney campaign would be smart to name a running mate soon — in part, he said, because the Democrats already are in “full-time campaign mode.”

“The drawbacks are you lose the surprise and excitement of the convention,” Duprey said. “Big deal. Who cares? Surprise is overrated. This is an election about competence and reviving our economy, and I think it shows seriousness of purpose if you pick your person earlier and you have them out on the road.”