I typed a response earlier, but my browser reset before I got it posted.
I don't do much down on the Lochsa when I'm off the river, except for drink, eat, sleep, and poop! If you're at Syringa, are you rafting with R.O.W.? I believe they have cabins/package deals with Bear Dance Lodge. Next commercial lodging upriver is at Lochsa Lodge at about mm 161.
Most boaters camp at Wilderness Gateway at mile marker 123
Some people camp at the Ghetto (Boulder Flats) on the highway side, at about mile 122.5.
Others camp at Ninemile (mile 129) or Knife Edge (mile 109).
Everything south of the highway is the Selway-Bitterroot Wilderness, so no biking there.
Jerry Johnson Hot Springs is at the Warm Springs trailhead at mile marker 151
Weir Hot springs is at mile marker 143
Stanley Hot springs is up behind Wilderness gateway. I understand it's a 6-8 mile hike and the trail fords Boulder Creek.