I assume Foreign Service due to retirement eligibility at 50? First, congrats on maxing out your TSP and Roth. I think keeping your money in a Lifecycle fund in TSP and a LifeStrategy fund in Roth is fine, but don't mix-and-match! Pick one target date for each (and don't add other funds) and plow the entire amount in it. Then you essentially have a simple, diversified two-fund portfolio. Nothing could be simpler or easier.
A propos, you've misinterpreted Thomas' advice:
thomasbayarea wrote:Investment based on risk tolerance:
0 - cash
2 - 4 year CDs (ladder OK)
4 - short term bond fund
6 - LifeStrategy Income
8 - LifeStrategy Conservative Growth
10 - LifeStrategy Moderate Growth
Bolding is mine. He is saying that, based on your risk tolerance on a scale of 1-10 (the bolded numbers), these are possible (exclusive) options, assuming you want the simplicity of holding all of your money in one place/fund. He wasn't advising that you hold all of these in equal weight. As others have intimated above, holding multiple target retirement funds with different dates is counterproductive.
Second, for the 200k+ in cash you've got, keep no more than 30k for your emergency fund. People advising you to do more are making assumptions, mainly that you'll need six months of expenses if you lose your job. Assuming you are tenured and not at risk of getting booted, you'll continue to have cash-flow surpluses throughout your career and will have plenty of cash on hand. I assume you also have either the BC/BS or FSBP health insurance, both of which are top-notch. Being crushed by an "emergency" is not going to happen to you. So you don't need to put half of that 200k+ into an emergency fund, at all. Instead, I would open a taxable account at a low-cost place like Vanguard or Fidelity and invest the vast majority of that lump of cash there.
As for what funds to put that cash into, I think definitely a low-cost international index stock fund (benchmark MSCI ACWI ex-US IMI) should be added to your portfolio because the "I fund" in TSP is extremely limited as an international fund (benchmark MSCI EAFE: only large cap, no Canada, no emerging/frontier markets). And more total U.S. stock market. But with that big of a sudden taxable purchase (which should be stock-based for tax efficiency), you will skew your overall AA heavily toward stocks. In which case, you may want to study up and create your own AA, which would mean ditching the L fund and LifeStrategy funds. If you don't want to do that, you can avoid having the stock-heavy portfolio by putting a portion of your TSP in F and G, separate from the L fund, to balance out the large taxable stock portfolio... or by purchasing things like TIPS, i-Bonds, etc. as fixed income to reskew your portfolio to be in line with the AA in your chosen Target Date funds.
Regarding the loans, don't pay them off if you are getting the SLRP (yes, depending on where you are posted). I paid the minimum and took SLRP until my outstanding student loans were too small to get the match, after which I paid them off in full.
One last thing: get Bogle's book "Common Sense" and read it. It's a good read and will answer many of your questions about AA, indexing, retirement goals, etc., and will help you understand the mindset of Bogleheads.
"Finance isn't rocket science, but you'd better understand it clearly." - Bill Bernstein