He was greeted warmly by the Saudis, in part because he signed an arms deal worth $109 billion and called on the Sunnis to act against Iran, (which had re-elected the moderate Rouhani to a second term) and the nuclear agreement ( even though his State Dept. has certified that Iran is respecting the deal.
He was accompanied by his wife, Melania and his daughter, Ivanka who made a speech on women empowerment, from which women reporters were kicked out. She, Ivanka could have stood up but chose to stoop down, exposing her hypocrisy and the sham. She preferred her business but was quite willing to use the issue of women empowerment. The venality matches her father's.
His next stop is Israel, where PM Netanyahu has forced all his ministers to show up to greet Trump ( news had leaked out that some of them were planning to boycott). The Israelis are angry about Trump leaking intelligence to the Russians that they provided to the US ( this was at the unprecedented meeting in the Oval Office with Russian Foreign Minister and also Ambassador, where Trump also joked about firing FBI Director Comey, and telling the Russians that that it was because of the pressure from the investigation of the alleged Russian hacking and interference in the last election, which has since led to the appointment of a special prosecutor, Moeller. The Israelis are very concerned about the arms deal, Trump signed with the Saudis.
The Israelis, especially Netanyahu want to curry favor with Trump, who they see as a strong ally, especially as he had promised ( during the campaign) to move the American Embassy to Jerusalem. He has backed down somewhat ( as he has done on a variety of other promises), so expect the treatment to be very good, but you can bet that they are going to get some " goodies" from Trump as a form of compensation.
Trump will need all the goodwill and treatment, because his next stop is the Pope, whom he insulted during the campaign and of whom the Pope has been very critical. This meeting will be cordial but not warm.
The real test will be Europe and the G-7 meeting. His anti-NATO, anti- European Union and his pro- Brexit, pro Le Pen stances have been galling and relations have been tense ( also the visit of Merkel did not go well ). What will he say and how it will be received and the treatment in the media and in the streets, will define this visit.
The trip has ended. It was not a disaster but there were embarrassment and thuggery. He elbowed the leader of Montenegro out of the to get in front of the camera. He lectured the heads of NATO, berating them for not paying their dues of 2% ( the 2% is for national defence spending not dues to NATO ( they were bemused, looking in askance at each other). He called the Germans "bad, bad ,bad", saying that he will limit car shipments ( most of the cars are made in US). He kept G-7 leaders waiting while he waited for a golf cart to take him to the photo-op. He also used the golf cart to go to the meeting in Sicily ( the others walked to the place of meeting). He ( privately) mused about leaving the Paris accord on climate change. He told the president of Israel ( when he was in Israel ) that he had just left the Middle East). He was admonished by Theresa May on intelligence leaks on Manchester bomb attack. He kept apart in Europe but cozied up with the tyrannical Saudis. He is back and tweeting about "fake news".