Hi @LivBooth and thanks for saying hello! You're making this super easy, I think... If you love your Altra trail shoes, I would look at their road running models for walking on pavement.
You didn't mention if you were looking for men's or women's models, so I'm including links to women's models, but most come in both fits. So here are a couple of options for urban walking from the good folks at Altra:
The Escalante 2 is a very popular model with our customers. It's lightweight and tends to fit a lot of feet well.
The Torin 4 is a cushier ride than the Escalante. I would call it a medium cushion in Astra's line.
The Paradigm 4.5 is the big cushion model! It has a plush ride. Some people love the feel, others want a shoe that's more "responsive".
If you want to try something other than an Altra, let us know and we can provide some more recommendations!
Have fun out there!