It’s fairly easy, strava heatmap and segment explore is your friend here (don’t know much about Trailforks).
If you’re near the visitor centre, you can choose from either side of the forest, and there is stuff available in both.
On the Bogle crag side, stuff available (according to reports) is
Descent to esthwaite water from the Fox sculpture (normally called The Fox)
Breasty Haw (Great Wood) – might be a couple of trees to hop over. The normal continuation to that is devils gallop/hole in the wall, so you’ll have to hack up the road to continue. There is a potential bridleway climb back up close by, don’t know if that’s OK.
Boulder Alley – byway from fox sculpture to VC.
On the other side, the North Face trail appears completely closed, still.
Open stuff: Grandad, dad and dentist (three witches) into Satterthwaite
Riverbed/Bacon Slicer – bridleway heading towards VC from crossroads at top of forest. The short but fun continuation after the fire road was shut last time I went past.
Parkamoor including the descent to Nibthwaite all fine, disappointingly not much of the sanitisation has washed away yet.
Lawson Park descent blocked in the top half, will be for some time. Bottom half fine. The next bridleway north also apparently OK.
As I mentioned, Broughton Moor Forest bridleways on the Walna Scar loop are not available. But you can loop around to Stephenson Ground or up to Natty Bridge using fire-roads.
Finally, Claife Heights is normally a good add-on for a Grizedale ride. The Harrow Slack descent between Far Sawrey and the lakeshore was passable, but were a number of big trees down across it, so it’s not much fun. Descent from Guide Posts to Colthouse fine except at the very top, but passable. Don’t know about Guide Posts to Belle Grange and the descent to Near Sawrey via Moss Eccles is mostly out of the trees.