Thanks for the replies! Here's what happened (best I can recall and describe):
encounter 1 - yellow lab, we've had previous incidents, and he's a frequent, unwelcome visitor in our yard: We got to the end of our drive, lab saw us and began to bark. Katie was alert, but relatively calm. As we walked away from his house, he continued to bark and follow us, and eventually walked up our drive. Katie remained alert, stopping several times to look behind us. I don't think she barked.
encounter 2 - tiny grey dog (maybe small terrier mix?), have not seen previously: He ran down his drive and into the street, ran up to Katie. He had a high pitched bark / yip. Katie was alert, but didn't really bark. We walked away when the owner retrieved his dog. I'll note that he was the only owner who intervened and he was the dog I was least worried about.
Between encounters 2 and 3, we passed several barking dogs contained behind physical fences. Katie was more alert to them than normal, but she didn't bark back.
encounter 3 - border collie or Aussie and chow, we've seen them in their yard and on walks: Both dogs ran into the street, barking. Katie jumped around a bit and barked back. We were able to continue and I got her attention back on me quickly.
encounter 4 - same yellow lab as encounter 1: This time we had to pass his house. I kept Katie's attention on me as long as I could. The lab barked and ran into the street towards us. At this point, Katie was barking back and wasn't so much interested in focusing on me. I yelled at the dog to go home. He did turn around and walk down the street in the opposite direction.
I should say that in the recent past, we have had dogs run up to us and Katie hasn't really reacted beyond being interested/alert. However, they've been one-encounter walks, not loose and/or barking dogs at every turn.
Katie is generally very friendly and likes to play with other dogs (on her terms). That said, I don't think she'd be one to back down from a fight. In our training class last week, our instructor called her "tough as nails."
Harleyboysmom, ironically, we started taking this route because there have been fewer dogs! When there's more light in the evening, we walk in local parks where all dogs are on-leash. Unfortunately, we don't have enough time for an after-work park trip this time of year.