The Bruksleden trail system is a classic Swedish trail system which winds through moss covered forests, through bogs, and over granite outcroppings. The lower section of the system has various split offs (which is more unique to Bruksleden than others which are mostly point-to-point trails). Near to the city of Västerås, one can do a complete loop of the lower trails which maps out at just a hair over 50k, and has only 1k of repeated trail. Start and end point are at the Bruksleden trail sign at the start of the access trail by the Erikslund Shopping Center parking lot. You can easily park there, 50m from the trailhead, and leave your car without worry.
There are some spots to get water throughout, but some of those are in dubious looking lakes and "streams," there is one good spring about 12k in when moving clockwise (if you reach the camping shelter you just passed it), and another well-like thing.... hard to find... maybe 15-20k from the finish in the same direction. That said, if you're not shy about dipping your bottle into a lake or "stream," you can easily get by with two bottles (three if you're taking it easy).
The trails seems to be slightly less technical/faster on the west side, and east side is rather boggy, so the direction to achieve the fastest result is questionable, but as of this writing the opinion is that going clockwise may be slightly faster.
While the length (50k) isn't particularly long, the beauty of the trail, with almost all of it being unrepeated, <<5% being anything but singletrack (some dirt road running), access to water, and proximity to a city, this should really be a classic test piece/training ground run. But visitors to Sweden be forewarned: a "flat 50k" on these trails will take you longer than you would expect.
Update: So, the official Bruksleden trail has been changed! And that makes the 51k LONGER by about 4km.
FKT attempt Aug 22nd 2020 in counterclockwise direction. I failed, too slow, did not have the speed that is needed in that terrain. Probably also a bad idea to try during summer time with a lot of vegetation. Next time I will try clockwise and during autumn or spring. The bridge is gone and the re-routed part of Bruksleden is longer. On the other hand it is possible to pass the small stream without the bridge but it took some extra time. I carried 3 liter of water to not use questionable water quality from the water spots, but a warm day as today, I would have preferred to be able to drink more water than I did.
Interestingly, Jakob pointed out that my GPX file from my Aug 2020 FKT on the new route has the time right, but is missing a bunch of the start data. I THINK what happened is that my watch didn't GPX lock in the beginning, which in itself is odd, since I damn well remember starting the watch in the parking lot by my car (not starting the activity though), ensuring I got a lock notice on the watch BEFORE starting the run. Either way, before I started the watch, I started GaiaGPS on my phone, then the watch, then when I finished pushed the watch, then pulled out the phone and stopped that. That data is here: https://www.gaiagps.com/datasummary/track/47cc27419d3d6c2437e6c39fb9b5677c/?layer=GaiaTopoRasterFeet
in case anyone wants to verify that I actually ran the damn thing!