Choclab, you should have no trouble making it to Outpost Camp from the Portal in a day. It is a 2000 ft elevation gain, and there likely won't be too much snow on the trail up to that point.
You haven't written much about your plans, but you might try hiking farther up the trail -- as far as you feel comfortable -- the next morning from Outpost.
Weather at the Portal is reportedly having highs at 50 - 60, so snow should be sparse.
This picture below, of the Lower Boy Scout Lake area on the North Fork is similar in elevation to Outpost Camp. It was taken March 9. I would think you should find bare ground to camp, but not sure. Maybe microspikes, like YakTrax, might be useful.
