Francisco de Simancas was present at the 1540 muster as a horseman in Vázquez de Coronado's company. There is also a good possibility that upon the return of the Expedition to New Spain, Francisco shipped out to the Philippines with several other fellow expeditionaries.
1540-1550:
1540, Feb: Muster in Flint & Flint, Documents, Document 12 [1 horse, native arms, Vázquez de Coronado's company]
?AGI, Patronato, 23, R.10 [Relación del viaje de Ruy López de Villalobos: Filipinas, 1542 [actually written between 1546 and 1549]; the fleet departed from el puerto de Juan Gallego on the día de todos santos, 1542 (thus, even people who completed the whole of the Coronado expedition could have sailed with Villalobos); día de los reyes, 1543, before reaching the Philippines the galera went down in a storm; then on January 23 they encountered natives who spoke Spanish; fols. 18v and 19r include a "Memoria de los castellanos que son vivos del armada de vuestra ilustrisima señoría;" on that list are don Alonso Manrique, Guido de Labozares, an Alonso Jiménez, a Diego López, a Juan Pérez, a Martín Sánchez, a Benavente, a Diego Sánchez de Cíbola, a Pero González, a Francisco de Simancas [probably the expeditionary], a Lorenzo Suárez de Figueroa, a Juan Gómez, a Juan Gallego, a Juan Gutiérrez de la Caballería, a Tórres, Pedro Martín de la Bermeja an Hernán Pérez, a Juan de Morales; latest date in document is in Lisbon August 1, 1548];
?Escalante Alvarado, Relación del viaje [p. 150: Villalobos expedition, a Francisco de Simancas is listed; so is a Lorenzo Suárez de Figueroa]
1570-1580:
?AGS, Contaduría de Mercedes, 268,22 [will, vecino and regidor of Zamora; married to doña Francisca Sierra; doña María Cornejo de Simancas, dau., married Pedro Pizarro of Peru; Francisco was in Arequipa; Juro a favor de Francisco de Simancas de 137.573 maravedís. Incluye: testamento de Francisco de Simancas, segunda mitad del siglo XVI: the original carta de privilegio is granted to Francisco de Simancas in 1557; the juro is to be paid from alcabalas de las ciudades de Salamanca and Ciudad Rodrigo; the document refers to the king having taken all gold and silver that came from the Indies in 1556, “en las flotas que vineron por capitanes generales Pero Meléndez de Valdés y Álvar Sánchez de Áviles,” which is evidently Francisco de Salamanca’s case (he’s been to the Indies, he could conceivably be our man’s relative); a testamento of a Francisco de Simancas is included in the expediente]
Other info: ?Sevilla del Río, Breve estudio [p.76: provincia of Colima, 35 encomenderos, Cristóbal Moreno (Moreno Trompeta); Xonacatlan, Coyutlan, Apamila were in his poder through the death of a Simancas]