If you want to keep your money in a target-date fund (which is fine), you should pick one where the target date is farther into the future. Remember, your real time horizon is your entire lifetime, which doesn't change just because you retired early. For that reason, I'd suggest going for something more like the 2060 target date fund.
Otherwise, a total stock market fund is good. Once you've got enough in the account to meet the minimum balance requirements and whatnot, you should also diversify to an international total stock index and eventually a bond fund. (For example, if you decided you wanted 30% of your holdings in
VGTSX, you'd buy into it when your total account value hit [$3000 fund minimum] / 30% = [$10000 account value]. Or you'd just go for the ETF version, where fund minimums don't matter.)
As far as Roth vs. traditional goes, you should be careful to capture the Saver's Credit if you can. Even if Roth is normally better because you expect to be taxed at a higher rate in the future, it can be wise to contribute
just enough as traditional to get your AGI down below either the $18,250, $19,750, or $30,500 cut-off (assuming you're single). See
Form 8880 for details.