You have diagnosed a 33-year-old woman with an ectopic pregnancy in the emergency department. Her vital signs are the following: HR 89, BP 112/74, RR 16, O2 sat 99%, temp 36.7. Ultrasound shows a 2.9 cm mass in the right fallopian tube with no fetal cardiac activity. There is no free fluid. Her hemoglobin is 121, blood type A negative, and serum beta-HCG 3200. Which of the following is most appropriate for her care?