There's a lot of information we don't know here. But assuming you've been investing for a few years, you probably have a decent amount for your age in your Roth IRA. You should write yourself up an investment policy statement and figure out your asset allocation. Since you are using ETFs, you can easily diversify your portfolio without having to purchase funds at a minimum of $3k each.
Lets say you wanted do the the
core four portfolio:
VTI (Total US Stock)
VNQ (US REIT)
VXUS (Total International Stock)
BND (Total US Bond)
You could pass on BND and eventually put bonds in your Traditional 401k through your employer after college. So all you'd need to do now is add VXUS to get some international allocation. Keep VNQ in your Roth and then VTI/VXUS could be placed in either the Roth or Taxable.
You could do an allocation of something like this for your stocks:
50% VTI
10% VNQ
40% VXUS
My Roth allocation is:
25% VTI (Total US Stock)
25% VXF (US Extended Market)
10% VNQ (US REITs)
15% VXUS (Total International)
15% VSS (International Small-Cap)
10% VWO (Emerging Markets)