You're doing everything right. A 50% savings rate is killer!
I'd do these things differently:
1) Finish off the student loan with the brokerage account money, because the 6% interest rate is eating up your gains.
2) Yes, contribute to a ROTH, but you can't put the max in the ROTH because your income is too high. Figure out what you can contribute, and do so.
http://www.rothira.com/roth-ira-limits3) Pay into the house instead of the brokerage account until you can get rid of the PMI. Then, go back to paying $1,300/mo + the rent income.
4) Look into an HSA or FSA.
As soon as you have access to the 401K, contribute the max, $17,500. That gets your income down to where you can also contribute the max to the ROTH, $5,500, which you should do every year. You'll still have plenty to put in the brokerage account, too.
Don't sweat the house. Your $1,300/mo mortgage payment on your 3-bed house is less than $1,800/mo rent for a one-bed apartment you wouldn't even own. If it's possible, raise the rent a little bit each year on the roommates. You could put that money toward the mortgage or into investments; with your low interest rate, though, I wouldn't be in a hurry to pay off the mortgage, just the PMI.