Not much singletrack in the Bedford-Sackville area that I know of. First Lake and Second Lake are pretty good crusher dust runs, but not singletrack. There are two sections of singletrack off the Second Lake Trail near the Trail head… one to the left, and one to the right. Rough and rocky, and best when trails have dried out well.
There used to be some old school singletrack by Sandy Lake and Jack’s Lake that you could connect up to the Range trails, but I haven’t been on those trails in a long time either.
Someone is working on a trail they’re calling “Project X” behind Cobequid Health Center (see “Project X” trail on Trailforks). Looks like it may be more of a downhill skill-park-type trail, but I haven’t ridden it.