sometimes, research will be more boring than what you expected, you might not have enough time to do what you like before you get tenured, if you could ever.
Since you are in U Iowa, getting into their PhD program would be your best scenario.
Otherwise, unless you have super strong RLs from super strong people, to be frank with you, your chance of getting into top 50 is slim. Check the student profiles of your target schools and see how your background compares to the current students' (I mean, not the general admission statistics, but click into the website of current students and see their background).