DA21
What are you going to take pictures of?
If you want help from this forum you need to provide more particulars other than telling us you're going to take pictures in NY, NY.
If it were me, I'd take both. Leave the DA40 on the camera and bring the DA70 in my pocket.
But, just so you know, I have neither lens.
IF I were going to NY I'd be taking street shots - photos of people going about their daily routine in the city:
https://www.pentaxforums.com/forums/mini-challenges-games-photo-stories/43981...-style%3D.html. For that I'd bring a wide angle, which for me would be my Sigma AF 24mm. I might bring the 18-55 kit lens also, 18mm @ f3.5 ain't bad. I'd also bring my Pentax-A 50/1.2 for some low light shot opportunities at night..
But that's me and that's how I take pictures.