This route is a mix of gravel, tarmac and trail, beginning and ending with a 29 km out-and-back section, with a 52 km loop in the middle. During the winter, large parts of it are designated for skiing.
Due to the unseasonal, heavy (28 cm?) snowfall on Tuesday, there was still 5-20 cm of dense snow/slush on >30% of the route, despite it being late April. The snowy sections were quite mentally and physically taxing, leaving me absolutely fatigued for the last, snow free 18 km through the central park.
Used this as an opportunity for food testing and consumed 4600 cal and almost 1000 g carbs. Pack weight 5 kg at the start, including 2,5 L of water. Refill from a lake in Vaakkoi (Saaren Musta, 40K) and from public taps in Salmi (49K - requires a code to enter the service building, not sure how you get it outside of the cafés opening hours except for calling ahead of time) and Pirttimäki (73K - the toilets are supposed to be locked outside of the cafés opening hours, but the door was open. There is also an outdoor tap next to the toilets but it looked broken). Haltia would be another good refill station if you pass by during its opening hours. Plenty of lakes en route too!
The route markings were quite sporadic and not at nearly every turn. Following a GPX track is highly recommended!