Way to auto-pilot your savings! Just a thought. So are you saying your 401k is maxed, your HSA is maxed, and your Roth IRA is maxed? If not, go back and fill them up. Do you have debt? How are you scaling it down? Do you plan to build debt? Do you have an emergency fund? Use efficient investment companies like your Vanguard; run from the JP Morgans, Morgan Stanleys, etc. If you do a taxable account, use tax efficient methods of investing. Bernstein in The Intelligent Asset Allocator p 145 gives some ideas on what to use. Don't put interest or dividend equities there, bonds, CDs, or indexes that frequently adjust their composition. Keep saving but spend some time reading before starting more funds. Possible books to start with: Burton Malkiel, The Random Walk Guide to Investing, Taylor Larimore, et. al., The Bogleheads’ Guide to Investing, Andrew Tobias, The Only Investment Guide You’ll Ever Need, Thomas Stanley and William Danko, The Millionaire Next Door.
Read about the total stock market index on Vanguard.