During the summer months of 1962 and 1963, she was awarded a scholarship to further operatic training with Boris Goldovsky's Opera Workshop at Oglebay Park, West Virginia. She continued for an additional summer in 1964 with the Goldovsky Workshop at Colorado Women's College and Northwestern University. While at the Goldovsky Workshop at Northwestern University is where Margaret met Rodney Stenborg, who would be her future husband.

Upon returning to Houston, Margaret resumed her music teaching duties with the Houston Independent School District at Alcott Elementary School. She continued to manage both teaching with professional singing. A recipient of several study grants in Houston including Phi Beta, Tuesday Music Club, Houston Music Teachers' Association and Girl's Musical Club, she placed second and third in the Metropolitan Opera Southwest Regional auditions in 1963 and 1964. In 1965, she was selected as one of the Most outstanding Young Women of the Year.

Her first professional operatic experience came when she joined the Houston Grand Opera chorus in 1959 under the direction of the late Walter Herbert, performing chorus and small roles until 1963. In 1965, she was chosen as soloist for a European concert tour with the Houston All-City Symphony Orchestra, performing concerts in Paris, Luxembourg, Frankfurt and Bayreuth. Later that same year, she enrolled at the Juilliard School of Music in New York, studying voice with Edith Piper and coaching opera with Ian Strasfogel and Christopher West.

While in New York, she became active with several choral groups including the Camerata Singers, Amor Artis Chorale, Musica Aeterna, American Opera Society and toured with the Robert Shaw Chorale throughout the South and Mid-West in a presentation of Handel;'s "Messiah", which was later recorded by RCA. She returned briefly to Houston in November of 1966 when Walter Herbert engaged her to perform the First Spirit in Mozart's "Magic Flute", a role which she earlier performed with the Juilliard Opera Theatre.

In 1968, she left for Germany as a result of Rodney's engagement as principal baritone with the Osnabrück Opera or Theater am Domhof . After a short leave of absence from singing, she later joined Rodney in the German theatre performing several roles besides choruses of opera and German operetta at the Staädtischen Bühnen in Oberhausen.

Returning to Houston from Germany in 1973, she resumed her music teaching duties at St. Christopher R. Catholic School. St. Christopher R. Catholic Church is where the Schwenders were members for many years. Margaret along with her brothers and sister attended the very same school where Margaret eventually herself taught.

During the 1976-77 season of the Houston Grand Opera, Margaret returned to rejoin the Houston Grand Opera chorus and sang with them until 1995. Her final solo performance with HGO was the role of Mrs. Hildebrandt in Kurt Weill's "Street Scene" which was an HGO co-production in Germany with the Theater am Pfalzbau in Ludwigshafen and the Theater des Westens in Berlin. The performances with the two German theatres took place from November 1994 to March, 1995.

In 1980, Margaret left St. Christopher to accept a more lucrative offer as music teacher at Mahaney School in Alief, TX just west of Houston. She remained at Mahaney until 1982 and then returned to teaching in the Houston Independent School District. She taught at two schools relatively near each other on alternate days: Gregg Elementary and Cornelius Math and Science Academy, which is a Magnet School. In the meantime, Margaret was selected for the Who's Who of American Women in 1985 in Music Education. Then the same year, Margaret left Gregg Elementary to teach music solely at Cornelius. She has shared the duties of being an elementary school music teacher at Cornelius from that time with her colleague and friend, Sherron Fowlkes up to the present Cornelius Elementary Music Program