I just got back from my lunch walk and I pushed it and did the 1.7 mile loop in 35 minutes. That's about 20 minutes a mile, which is not great, but it's not too bad considering I'm wearing my heavy hiking boots and a lot of that route is uphill, especially at the end. The 1.7 mile loop is also a great indicator of my mental fortitude, as there are opportunities to cut it short
I've already walked more in 3 days than I did all of last week. Here's a chart summarizing the last 10 weeks of walking plus the first 3 days of this week. My walking weeks start on Sunday.
As you can see, a good week is usually followed by a down week, which should get better as I lose more weight and stress my feet and knees less. I'm going to try for 10+ miles this week as I close in on my next goal of 280 lbs.