obvious, probably, but also, use the map...
Even with the big middle section of Darling Hill off limits, there's plenty to ride at KT.
Get a map -- they have them online now -- and you can also get one on the app Ondago, which is more official than just Trailforks.
Think in terms of sections. You could do each section as a "ride" or combine 'em into something more "epic."
On Darling Hill, the southern end could be called the Chapel Section. Do all of the trails starting with NewT (at the Wild Flower Inn) and work your way downriver (the West Branch) until you've done Bear Back. Then cross the road and do the Jaw/Knob stuff. That's about 15 miles.
Northern End has the Coronary section. Do all those trails and it's prob 8 miles. Make sure to get Harp, which is across a different dirt road.
The Burke Section. has the Camptown-Dead Moose Alley-etc etc-Moose Alley. You can climb all the way up the mountain using Burnham Up and Shire, or you can shuttle and park at Burke Mt. Resort and then get into Shire or Camptown.
The White School Section is somewhat self-contained and is another 8 or so miles if you do all the trails. You can also connect this with Moose Alley (which I put in the "Burke" section) and/or the Moose Haven section (below). I like to finish this section by crossing the street (E. Darling Hill Rd, the paved one) and hitting Herbs (up) and Kitchel (you can do Beat Bog too)
East Haven has the Moose Haven section. You could just drive and park there. If you climb the Haul Road (it's a fireroad, and it's pretty long) twice, you'll get about 10-12 miles depending on how you put things together. Ask the dude (ambassador) in the parking lot for tips, but make sure you go all the way to the very top of Black Bear, where you'll find a new gazebo in a field. (see other post that suggests going up to Swamp Donkey first)
have fun!