Update in terms of our FIRE situation, we aren't in a huge hurry to retire. We both love our jobs and save about 40-50% of our incomes which can vary a lot year to year as we are both freelance. I'd say we are way better than the average American, but way behind the typical mustachian. All that to say, we are happy where we are. I also wouldn't really know where to put that much money without major tax implications.
On taxes:
Depending on where it physically comes from on the decedent's side of things, it probably has little or no tax consequences when you receive it. There are some oddball situations with very large estates (> $5mil or so). There are some financial instruments that may create taxes on cashout (annuities, some small percentage of insurance policies, stocks/bonds held in trusts, etc) where the tax will be applied to the estate and then passed on to the beneficiaries in the next tax year with a K-1. But PROBABLY, taxes are minimal to zero as a percentage of the $250k.
As to taxes related to where you put this money afterwards, see MDM's investment order:
https://forum.mrmoneymustache.com/investor-alley/investment-order/msg1333153/#msg1333153. This is generalized and doesn't fit EVERY situation, but fits MOST situations.
"Taxable" investment accounts seem to be poopooed here... but take that with a grain of salt. They're not as good as tax deferred growth, but they are still very tax friendly IMO. Dividends and cap gains are always taxed below your current tax rate. If you are married filing jointly, you can actually pay 0% on dividends/gains if you can engineer your taxable income below $75,900. They're only 15% for pretty much everyone else. (If you make over $470k taxable, they start to creep up, though still below your normal taxable rate.)
