Bummer that I am in section 115 because I will be alone too. But I love Muse so much that is it worth going alone to the concert!! I NEVER sit for a Muse concert and most people don't either, so expect to use your seat only while you wait for the band to come on stage or while the first act is playing and they clear down to set up for Muse. Inside the Wells Fargo is cool but not chilly. But once the concert starts and the dancing begins it warms up quickly! Since its January, Ill just stuff my jacket somewhere in the meantime. I wouldn't recommend standing on the seats. I have never seen it done there and will be probably very frowned upon. I am only 5'4" so I feel your pain, which is the reason I don't do general admission. The seats are slightly staged going up, so even if someone taller is in front of you, you can usually see in between or around them. If your near an aisle, you'll be golden!!
Hope that helps....a Muse concert is a truly awesome concert experience!!