re: Starting 401k independent of employer (not offered)

I don't know what IC status is, but if you aren't self employed and your job offers no benefits, then yes.

Two things to consider though:

1) you could put it in a Roth IRA, which while it has the same limit, 5500 in post tax dollars are worth more than pretax dollars.

2) there is no requirement to have your retirement exclusively in a retirement account. You can skirt the edges of the tax code to do this efficiently. (I.e growth heavy funds who focus on capital growth rather than distributions)