Welcome to the board, T&T.
As the title states I'm an AD military member in the USAF. Currently been in 8 yrs and plan on contributing another 12 yrs to hit my 20.
One of the major regrets of my career was gutting it out to 20. I'd suggest that you take it one obligation at a time. Keep on going as long as it's challenging and fulfilling, but when the fun stops then be ready to make the transition to the Reserve/Guard. Don't just grimly clench your jaw and hang on for the active-duty pension. You'll risk your physical, mental, and relationship health.
The Reserve/Guard pension at age 60 still includes inflation protection and free healthcare, which are the most important factors. You'll still be able to achieve financial independence in your 40s on your own savings, especially because they only need to bridge the gap until your pension starts.
I'm debt free, own some PMs and "try" to live within my means.
I don't recognize the acronym. What's a PM?
My questions is what would you recommend investing $10K in? Real Estate lots (NW FL), PMs, stock market? Totally clueless as what to do. I would be willing to tie up $5K 3-5 yrs in S&P 500. My risk tolerance concerning $5K is rather moderate-to high if that helps in determining.
The first thing I'd do is maximize my contribution to my Roth TSP account. I'd boost my payroll deductions to it and live off the $10K until I'd maxed the Roth TSP.
Next I'd maximize my Roth IRA contributions, and then I'd try to save even more in taxable accounts.
However your "clueless" comment is an indication of a deeper issue: before picking any investments I'd decide on an asset allocation. Since you're in the military with a relatively stable income, you can afford to take more risk-- especially volatility risk. As other posters have mentioned, read about the basics and asset allocation and pick the one which works for you. Another starting point is the AA portion of the Bogleheads Wiki:
https://www.bogleheads.org/wiki/Bogleheads®_investing_start-up_kit
https://www.bogleheads.org/wiki/Asset_allocation
One example (suitable for active-duty servicemembers) would be 80% equities and 20% cash (high-yield CDs). (If you stay in the military long enough to earn a pension then you'll never need to invest in bonds.) If you're even more aggressive then you could go to 95%/5%. You could invest your Roth TSP in the C, S, and I funds-- or just default to the L2050 fund. In your Roth IRA and taxable accounts you could choose the equivalents of the TSP funds or just go with a total stock market fund.
The key is reading about asset allocation to the point where you're comfortable with your choices and sleep soundly at night. If you're not emotionally satisfied with your AA then it doesn't matter how logical your selection may be. Behavioral financial psychology will trump rational thought.
I'd appreciate some sound advice from others. I know $10K isn't "a lot" but I thought instead of it sitting in a savings account I would rather invest it.
The best action you can take with the $10K is to invest it in an asset allocation that you'll be willing to keep for the next 10-20 years. Then you can automate your payroll deductions to your Roth TSP and your Roth IRAs, and send even more to your taxable accounts.
The real path to financial independence is not being a brilliant investor. A high-equity asset allocation using passively-managed stock index funds with low expense ratios will give you 99.9% of the market's return with about 5% of the effort. Once you set that up, you can focus on a high savings rate (low expenses and a higher salary). A 40% savings rate for about 20 years will get you to financial independence even without a military pension.
How many years does it take to become financially independent? - Military Guide
You can read "The Military Guide To Financial Independence And Retirement" at your base or public library. Much of the book is excerpted in the first six months of blog posts from the archives:
Post titles by month - Military Guide
Or just keep asking questions here.