Sorry you got a flat. I have been trying to take extra measures to chop up the thorns after a clearing so that there are fewer thorns left over. Actually this weekend I did the eastern loop over two days but mowed each section after the clearing on the "mulching" setting.
I got tired of flats from riding here so I took Werner's advice (Thanks Werner!) and bought some of those inner liners for the tires to protect the tube from smaller/shorter punctures. Plus I use a little Slime in the tires. I don't wanna jinx myself (knocks on wood) but so far this year with these updates and my extra mowing I've had only one flat. And that thorn was a big one, likely from a hawthorn tree!
The northwest loop is the split in the long wooded section that is the last part of the trail. You can go right to add an extra mile to the trail through an out-and-back path before it splits in the woods for a loop. Its the section where there is a huge rock which I put a short log in front of it to help to transition a ride over the top of it. This loop also takes you to another smaller pond and past part of the northern stretch of the Hewen's Creek.
I rode the eastern loop myself tonight, jumping on from the "semi-secret" entrance along Hitchingham. This is actually where I ride in with the mower, so it's more of a utilitarian access then anything else. It's also the place where I confuse a lot of riders who think that they should go right there and they get taken right out to the road. I temporarily setup a part of a tree to try to "steer" riders left, which I hope will last until I can get some signs setup.