I came across an interesting article, "The Rosary and Eucharistic Adoration," by Susan Benofy from May, 1999 in the Adoremus Bulletin. Adoremus - the Society for the Renewal of the Sacred Liturgy promotes authentic reform of the liturgy.
Benofy does a very good job of addressing concerns that the Rosary is not an appropriate devotion done before the Blessed Sacrament. Benofy shows how the Congregation for Divine Worship (CDW) and various popes have explained what the Rosary is and how that is thoroughly compatible with Eucharistic adoration, given the proper disposition of the faithful. This was, apparently, a bit of a reversal of position by the CDW from a 1968 statement which concluded that the Rosary was a prayer addressed to Mary and therefore not appropriate for Eucharistic adoration.
However, in a 1999 document, the CDW cites Paul VI's Marialis Cultus , which affirms the Rosary as Christ-centered:
As a Gospel prayer, centered on the mystery of the redemptive Incarnation, the Rosary is therefore a prayer with a clearly Christological orientation. Its most characteristic element, in fact, the litany-like succession of Hail Mary's, becomes in itself an unceasing praise of Christ, who is the ultimate object both of the angel's announcement and of the greeting of the mother of John the Baptist: "Blessed is the fruit of your womb" (Lk. 1:42). (section 46)
In his apostolic letter, Rosarium Virginis Mariae, John Paul II writes:
The Rosary, though clearly Marian in character, is at heart a Christocentric prayer.... With the Rosary, the Christian people sits at the school of Mary and is led to contemplate the beauty on the face of Christ and to experience the depths of his love. (section 1)
Brant Pitre discusses the Jewish roots of the Eucharist, and in doing so highlights the bread of the presence in the temple as a type of the Eucharist. The word for "presence" in that phrase can also be translated "face." Both John Paul II and Pitre show us that the Rosary and the Eucharist are complementary ways of encountering the face of Christ.
John Paul II goes into great depth connecting Mary and the Eucharist in his encyclical, Ecclesia de Eucharistia, where he speaks of "Mary, Woman of the Eucharist" (Chapter 6). Of course, his addition of the Luminous Mysteries includes the Institution of the Eucharist, which makes the Rosary even more obviously Eucharistic. However, even in the original mysteries, he sees profoundly Eucharistic connections:
In a certain sense Mary lived her Eucharistic faith even before the institution of the Eucharist, by the very fact that she offered her virginal womb for the Incarnation of God's Word. The Eucharist, while commemorating the passion and resurrection, is also in continuity with the incarnation. At the Annunciation Mary conceived the Son of God in the physical reality of his body and blood, thus anticipating within herself what to some degree happens sacramentally in every believer who receives, under the signs of bread and wine, the Lord's body and blood.
As a result, there is a profound analogy between the Fiat which Mary said in reply to the angel, and the Amen which every believer says when receiving the body of the Lord. Mary was asked to believe that the One whom she conceived “through the Holy Spirit” was “the Son of God” (Lk 1:30-35). In continuity with the Virgin's faith, in the Eucharistic mystery we are asked to believe that the same Jesus Christ, Son of God and Son of Mary, becomes present in his full humanity and divinity under the signs of bread and wine.
“Blessed is she who believed” (Lk 1:45). Mary also anticipated, in the mystery of the incarnation, the Church's Eucharistic faith. When, at the Visitation, she bore in her womb the Word made flesh, she became in some way a “tabernacle” – the first “tabernacle” in history – in which the Son of God, still invisible to our human gaze, allowed himself to be adored by Elizabeth, radiating his light as it were through the eyes and the voice of Mary. And is not the enraptured gaze of Mary as she contemplated the face of the newborn Christ and cradled him in her arms that unparalleled model of love which should inspire us every time we receive Eucharistic communion? (section 55)
Finally, there is a good address by Cardinal Archbishop Sean O'Malley of Boston on "Mary and the Eucharist." He gave this at a Eucharistic congress, and it is specifically on the the Sixth Chapter of Ecclesia de Eucharistia. Cardinal O'Malley is clearly comfortable combining the Rosary with Eucharistic adoration:
Allow me to share with you some of my personal meditations on the Joyful Mysteries of the rosary. These are the mysteries I like to use when I am praying the rosary during a holy hour before the Blessed Sacrament.
It is important that we think about what we are doing and saying when praying the Rosary in Eucharistic adoration. Such clarifications are important, given the principle of lex orandi, lex credendi (literally "the law of praying, the law of believing," meaning that how we pray forms what we believe). We can be thankful for the clarifications given by these people and others, which help us to draw closer to our Savior in the Blessed Sacrament.