I also lean toward RB, but with picking up Kamara and already having Sanders I think I'm pretty well set at RB. The fact that I don't draft again until #20 is why I'm think QB at #4. All the top QB's will definitely be gone by #20. I have Prescott, Murray, Watson and Wilson as my tier 2 QB's and expect them to be gone by #20. My Tier 3's are Ryan, Allen, Brees and Brady. They will probably be gone also, so I would probably have to chose either Stafford, Daniel Jones, Aaron Rogers or Big Ben as my #1 QB.
As I write that, I'm thinking it really depends on who is the BPA at #4. I would really like having Tyreek Hill or Travis Kelce and not sure how bad off I'd be with one of those tier 4 QB's mentioned above.