Welcome aboard. There's nothing at all wrong with investing in target retirement funds, most people who don't want to bother with investing would be better off with target funds instead of buying various funds for sketchy reasons (misc hot tips from TV, magazines, brother-in-law, neighbor, co-worker, etc.).
You really don't need to make it complicated, the next logical step for you is a lazy portfolio, most hold anywhere from 3 to 10 funds representing different asset classes. Here's a primer from a good resource IMO...Put Sloth to Work for You - Registered Investment Advisor
. You'll find many here have (large) portfolios that are 10 funds or less, even though they've been investing for decades. Unless you want to be a full time investor, there's no need to get more complicated.
And here are examples of a few other lazy portfolios MintLife Blog | Personal Finance News & Advice | The Lazy Portfolio: Asset Allocation Made Easy
- No reason to rush into anything, you're fine with target funds until you decide how you want to proceed.
- Some people make the mistake of building lazy portfolios in each of their accounts, that's not necessary or ever desirable. Once you choose the asset allocation and specific funds you want to hold, you can place them for tax efficiency. Most people would hold equity funds in taxable accounts and fixed income in tax sheltered accounts for example, though it appears your accounts are mostly tax sheltered.