From George H.W. Bush. Former Pres. Bush and Reagan were not friends like Clinton-Gore '92 or Clinton-Gore '96. Reagan defeated Bush in a somewhat feisty primary campaign and actually chose him to be VP because Reagan rejected Gerald Ford's major condition for accepting the VP post under Reagan -- Ford's control of foreign policy. Reagan rejected the semi-appeasing realpolitik approach that Ford and Kissinger preferred in dealing with the USSR because Reagan wanted a more aggressive and confrontational approach that challenged the USSR's legitimacys.
Some details of that are here in the New York Times archive in an article by Reagan's first NSA, Richard Allen (although Michael Deaver and Ed Meese later wrote a letter to the editor questioning Allen's memory of events).
Here is an excerpt regarding Bush, Reagan and their mutual respect from a Policy Review article describing the VP position and its evolution:
Although their respective staffs had not “meshed” as well as those of their predecessors, Ronald Reagan and George Bush devised a working relationship that, while not as personally close as the one between Carter and Mondale, exuded equal respect and trust. It began with Reagan’s willingness to set aside “voodoo economics” and other criticism Bush had leveled against him and his proposals when they were competing for the 1980 presidential nomination.
With Reaganites simmering over the influence of “Bushies” in Reagan’s administration, Reagan named Bush’s friend and former campaign manager James Baker his chief of staff and retained other Bush advisers . . . in high posts. Like Eisenhower and Ford, Reagan assigned Bush some line responsibility and called upon him during crises. Bush chaired Reagan’s Task Force on Regulatory Relief and served as foreign policy “short stop” between dueling Secretary of State Alexander Haig and National Security Adviser Richard Allen.
Bush earned the trust of Reagan’s inner circle through the dignity, reminiscent of Nixon’s, with which he comported himself while Reagan was recovering from a near-fatal assassination attempt. Mindful of Rockefeller’s experience, he avoided situations that placed him at odds with senior administration aides and conserved his time by delegating much of his line responsibility to trusted and competent aides such as his counsel, C. Boyden Gray.
Bush upgraded the vice president’s staff operation on Capitol Hill, where he actively lobbied on behalf of Reagan proposals. He regularly attended meetings of Senate committee chairmen, sat in on its Policy Conference, and kept up old ties with friends he had made through his years of service in the House.
Like Rockefeller and Mondale, Bush used his occasions alone with the president to share his views on policy matters. As a former CIA director, UN ambassador, and China envoy, he brought a unique perspective on foreign affairs. Nancy Reagan later remembered that her husband valued these meetings because he knew with certainty that nothing he and Bush discussed would be leaked.