schwab now beats Vanguard for lowest fees and it's only $100 to open a mutual fund

I'd avoid any of the "Target Retirement" funds. There are lots of articles out there showing why these are a bad idea. If you want stock and bonds (that's all they are), put your money into the Vanguard Total Bond Index fund and the Vanguard Total Stock Market fund (this mirrors the Wilshire 4000 index).

The advantage of holding an ETF instead of a mutual fund is that you can sell covered calls against an ETF like the SPY (even in a retirement account). For example, you can go out to September and sell 96 strike calls (75% chance of being out of the money) and pick up about 1.25% in premium. If the S&P 500 goes up 15% between now and September, you'll be forced to sell your shares but you'll have picked up 16.25% in 2 months. Once September passes, repeat for December; then repeat for March; etc. You should be able to pick up roughly 2% each time (we're just 2 months away from September expiration instead of 3 now). That's an extra 8%, compounded due to reinvestment, return each year, on top of the underlying index movement (which would be up or down).

Having this option is the advantage of having ETFs. Currently, Vanguard has outrageous fees associated with options trading, so go with TD Ameritrade or some other discount broker if you want to do this.