The Big Wood River will fish very good in the month of March. As the temperatures warm up expect very good midge fishing. You will want dries and nymphs for this time of year. Pattern size will be critical and I like very small flies for this time of year. My favorite dries are Trailing Shuck Midges and griffith’s Gnats on top. Be aware that you might see them bulging for these flies on top but many times they want a fly just under the surface. Tungsten Zebras and other bead head nymphs will work but you also need nymphs that sink gently and are presented just under the surface. I like Midge Biots and WD 40’s in sizes 22-24 when the fish are feeding on this stage of insects. I will fish these patterns behind an Adams Parachute so I have a reference where the fly is. I like the smaller fly at least a couple of feet behind the Adams so the drift looks natural. If I’m using a nymph I usually have the dropper less than a couple of feet and use the bigger dry as a strike indicator.
The Big Lost should be great in March. Midges and BWO’s will hatch as we get warmer days and the nymphing is always good. Rainbow Warriors, Zebra Midges and Brassies in small sizes will work underneath. You will need 6x for the dry fly fishing as the water will be low and clear. The drive over is just shy of 2 hours but it is well worth your time.
Steelhead fishing will start sometime in the middle of March with the main run showing up in Stanley in early April. You will want to get closer to Chalis and Salmon in early March and the fishing will probably be very good with Fish and Game just announcing increased limits this year. I like spey casting and swing flies or you can nymph in the deeper pools. 
