Damn, 7k spendings a month - remind me not to have kids.
How to save / invest for retirement is based on a few factors, like:
How much money do you want to spend each year after retirement?
How much average inflation do you think there'll be?
The link I put has some formulas you can plugin to figure out how much you need to have by the time you retire.
Also, how much risk do you wanna take? As an example, trailing 60y inflated adjusted returns for SP500 is 5.05% or so. So your spending power will increase 5%. But SP500 could be volatile and if you absolutely need the money (which you probably will since your run rate is like 7 months). For high diversification you might want to do something like the all weather portfolio:
1. Stocks (maybe 30%)
2. Diversified commodities(maybe 7.5%) like corn, oil, etc.
3. Some bonds (15% on short term bonds and 40% on long term bonds)
4. Precious metals (7.5%).
One thing I don't like about the above is 30% on domestic stocks. You can probably look into doing maybe a 15-15 and/or 20-10 of domestic vs. international stocks instead.
Google Sharpe ratio for each and see how it fits in your projected spending and risk tolerance.