Following prob_lems advice to increase running distance no more than 10%/week, I'm now up to 6.05km.
I think tomorrow I'll go back to my conventional run along the southeast edge doubling back when I get halfway -- I just had never gone along the west route before. (There's actually tennis courts there now, and a parking lot -- all of which are newer than the Google map photo.)
I tried the new route, initially, because I wanted to avoid disturbing the cows that graze in the field that have been near the trail for the past week or so. mackys was kind enough to tell me that runner fatalities due to cow attack occur a few times a year. I'm not so sure how dangerous the average bovine is to a jogger, but I do keep my eyes on them, and turn the music down so I don't miss any enraged bellowing Holstein battle-trumpet.
I think I'm going to continue the run down the east edge and double back when I hit 'halfway' distance.
I go in 1hr to see the place I'm considering moving to ... will have to investigate new running paths based on this.
[EDIT: Meh! Yesterday I went down along the east edge and not only was there one outlying cow (who heard me and ambled down off the trail), there were about six standing all around further down, who just stood and stared at me as I approached. I stopped, they stared, I turned back around and went the other way. C'est la vaches.]