The above image shows both the Rice Creek and Sherman Lake singletrack trailheads and some parking spots. The Centerville Boat Launch parking comes with a $7 vehicle fee.
These trails were new in 2022. I did them with some young novice riders and they worked well. The overall system is larger than it looks and mixes a new modern flow trail area with legacy singletrack and many bandit trails. As of May 2023 they are not yet in Trailforks but the Sherman Lake section is in MTB Project, they have a MORC page (I think map is from MTB Project so only shows Sherman Lake today), a Trailbot entry as "Rice Creek Chain of Lakes" and a Facebook Page. There's a Facebook Group for volunteers.
Now Bikes (Arden Hills?) runs a semi-regular Sunday morning ride from the Rice Creek Elementary parking lot (The pedestrian bridge is technically closed for repair summer 2023).
"many miles of trails in at least five different nodes of the park. The trails are heavily wooded and surrounded by lakes. There are sections where biking or hiking on paved trails is required to get to the next node."
Official trailhead per Google Maps: 45°09'47.7"N 93°06'16.4"W. I've never parked there however.
We park at the Kelling woods: 45°9′48″ N 93°6′43″ W entrance. Follow the old dirt road past the closed gate (to keep out cars) and go straight on. It's a pleasant fun trail that branches to some bandit trails but keep going straight and come out on the paved trail. Turn left and in a short time you come to a purpose built system. It's flowy and loopy with some good starter climbs. I recommend two laps. Although it's a green novice trail it does have an optional gap jump!
If conditions are dry you can park just a bit to the west at the Rice Creek Canoe Launch. There's a winding trail that will also take you to the formal system. I actually prefer this route but it's often quite wet and even underwater in places. So only good on dry days.
Some comments from a 2022 Facebook post:
There is another terrain park on the other side of the golf course. Following what is labeled as F Street on the map (actually all bike trail), the other terrain park is between Centerville lake and Sherman lake. There are also 5 single track trails between the 2 terrain parks. I make a loop from my house to hit the 7 features and takes about 1.5 hours, about 12 miles.
And a map from the same post by David L (ride recording)
The Rice Lake Singletrack can be accessed from Aqua Lane, riding the paved trail south to the trail entrance on your left, which is well marked and has a gate and signage. If you get to the long pedestrian bridge, you’ve gone too far south.You can also access it by going north from Rice Lake Elementary School (575 Birch St, Lino Lakes, MN 55014), over the pedestrian bridge, and another quarter mile or so north: it would then be on your right
... park at Laurie Lamotte Park, plenty of parking and easy to get to from 35e. Follow the paved trail around to the Sherman lake trails (0.6 miles) … take the bandit trails to the other trails by Aqua lane.