Welcome to the Eastern Sierra! Mescalito looks great. How do you plan to protect the Bismark pitch?
The weather will most likely warm up over the next few days. There are several good weather forecasts. The two I use are Dennis Mattison's forecast and NOAA. Here are links:
NOAA Eastern Sierra Weather: this will give you the Eastern Sierra and there's a map where you can click to get a pinpointed forecast for anywhere.
Dennis Mattison's Forecast: Dennis is a meteorologist who has his own weather stations in the area. He's been pretty accurate for my purposes.
Is there anything else you'd recommend for training that might be closer and easier to access?
While you're in the area you should climb Cardinal Pinnacle. It's a short approach and there are several great routes on it. The granite is some of the best around. It's north facing and if you wait for temperatures to drop you'll get some great training. I saw another party once using it for training for Baffin Island

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If we do go to Russell where would you recommend we camp? Upper boyscout lake or Iceburg lake?
If you camp at Upper Boy Scout Lake you'll be lower in elevation so the nights will be slightly warmer. Your approaches will be longer which shouldn't be a problem since you don't want super early starts anyway. You could descend the East Ridge instead of the SW chute. Given the recent snow that route will be sketchy now though. It has a lot of down sloping slabs on it that'll be slick with the fresh snow.
I assume we need to get permits for this?
Yes you need permits. You can get them at the Interagency Visitor's Center just south of Lone Pine. If you go in a day or two before you want to enter you'll be able to get walk-in permits. There's not guarantee but it's rare people don't get them this time of year after a storm

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