The duo didn't seem in any rush to escape each other's company, even taking time to grab some coffee at Starbucks while there.
So what's going on with these two kids?
"Had a perfect 2 days with my best friend. Shamrock shake!," Ashlee offered this afternoon via Twitter.
Well, all appears to be going pretty smoothly on the friends front for the former couple. As the Fall Out Boy recently told E! News' Ryan Seacrest, despite Ashlee filing for divorce in February, he considered her his "best friend" and that they are trying to stay on good terms because of Bronx.
"Ashlee's been my best friend for five years; she's the mother of my child. I have nothing but love and respect for her and going through something like this isn't easy, but we're friends and the most important thing is to put our son first," Wentz said earlier this month.
In her divorce petition, Ashlee requested joint legal custody but sole physical custody of Bronx, with Pete firing back with his own papers in response requesting both legal and physical joint custody of the 2-year-old.
"Bronx is doing awesome," Wentz said. "It's something new every day. Everything's a new discovery for him. He's opening doors and he wants to paint. He hides cell phones and credit cards."
And so far he's doing a good job of keeping his parents' split amicable.