re: 19k from previous employer 401k

You can increase your emergency fund by investing in a Roth IRA (if eligible) if you don't feel 2 - 3 months provides enough cushion. That way you don't have too much idle cash.

I personally like Vanguard ETFs like VTI or VOO (both are stock index funds).

You may consider retirement date funds as they are great for people who don't have the time and/or interest to track investments and allocations.

Make sure to be aware fees before you invest. It does make a significant difference over 25 years.