I have a big recommendation. I have a Shih Tzu and they are adorable. They run around, play games all day long, and they'll sit with you for hours. They're a lap dog in a way.
They don't get very big either.
I will say this. Shave their fur for the summer months. I do fur care almost daily, but it's worth it. They've been one of the best things to come into my life too. They're full of life.
I took them on a mile walk and it worked, but hmm... more than a mile. I have to wait till they're older.
You might want to get a lab. Labs are wonderful dogs for walking. My folks had one, but he passed away.
Edit: I carried him back with me from the mile walk. I'm reading where they walk longer when they're older. That's normal.
I found a video of someone taking theirs for a walk:
https://www.youtube.com/watch?v=PBd2CazsQ24