With the forest relatively close I would say that without a flashlight you will be completlely f***ed. Strongly recommended to bring one. Let me also add that the rating on the scale 1-10 for bike-friendly trail is around 9. Some long-cuts will be needed but maybe the nize hare will show them to any bikers. This also applies to hashers bringing a pram or two.
However: As I haven´t spoken to the patron yet, I´m not entirely sure we can go the venue in mind. If it turns out negative there´s a plan B. In any case the underground station to go to is still Kärrtorp and I will let You know any change or final confirmation ASAP.