Anacortes Community Forest Lands or ACFL is one of my favorite places to ride. Divided into 3 sections you can buy maps at many places within the city.

Years back Little Cranberry Lake was a staple ride. Heart Lake inbetween, and Whistle Lake a destination for the heartier riders who don't mind pedaling up lots of steep.

i'm posting this the route that i favor as a request, that i decided to post and share with the community in case anyone else out there wants to see what this area has to offer. Since there are many trails, many people have assorted routes. i built my knowledge of the trails from numerous visits, including a few months when i lived on the island working on the hospital.

This route will be around the equivalent of a Tiger ride. Without actual knowledge i will say it feels to be a 15 to 20 miler with 1500' plus cumulative elevation. i try to cherry pick descents that are fun, with viewpoints, interesting and challenging trails, and climbs that are not overbearing so you can use that energy for the tech.

Park at Heart Lake Parking.
(Use Whistle Lake Map)
Head South Heart Lake Road to Mt. Erie Road
Spin up pavement to 26 left
26 to 207 stay right to road 21
Stay left on Y continue on 21
Take right on 204
Left on road 20
Left on road 21
Right on road 27
Road eventually turns into trail
Take left on 300
Take right on 303
Take left on 302
Take right on 305
Take left staying on 305
Take right on 306
Ignore the next two right uphill climbs staying left on 306
Left on 311
Steep descent then a quick left on 314
Another left on 313
Sharp right down Road 21
Quick left on trail 320
Stay right on 215
Cross parking area, directly across Heart Lake road Heart Lake Trailhead
(Use Heart Lake Map)
up and left on 25 which turns into trail 212 staying left bypassing old viewpoint
Half mile later take left followed quickly by a left on 250
Left on 210 followed quickly by a left on 224
Left on 241 to Havekost Rd./A Ave.
(Use Little Cranberry Lake Map)
Cross road to 126
Trail T's take left uphill dumps you out on Road 10 Take right
Take left on 113
Take hard left on 124
Take left on 113
Spill out Road 10 Take right
Second left up Trail 115
Ignore right ignore left ignore right ignore left staying on 115
At T take left 116
Take right 118
Drop you down to 10 take left
third left return to Trail 115
Take first right Trail 111
Right 115
Left 110
Left 109
Stay right 109
Right 129
Left on Road 11
Left on Trail 105
Ignore 2 rights staying on 105
Right 128
Ignore Right/Left/Right staying on 128
Right 127
Across parking lot to 100
Ignore left and 2 rights staying on 100
Continue taking rights staying on 100
Take right up 104
Cross gravel road stay on 104
Left 108
Stay left, Stay right, Stay left, Take left on staying on 108
Cross Road 10 to 134 back to Road 10 take left
follow road back down to return to 126
Staying right on 126 backtrack to road
(Use Heart Lake Map)
Cross road backtrack 241
Left 224
Right 209
quick right 244
left on 210 stay right on 210
First left up steep climb
Take right on 242
Finish back to Heart Lake Parking

To make this easier you can cross reference the maps, using a highlighter trace out the route, and/or make a sequence of arrows with coordinating trail numbers. Hopefully this serves to be helpful, for if you enjoy roots, rocks, natural tech, and beautiful scenery, it's less than a 2 hr. drive up.