Welcome to the forum and thank you for your service!
Since you have no goal for the $175k, I think you can consider investing part or all of it as part of your retirement nest egg. If you change your mind and see that you'll need the money for a house down payment or something, you can adjust then. However, you could not make an adjustment this large during a market crash. So before going this route, be sure you can do what you want if a large part of that $175k is not available for several years.
Investing it all and staying at 85/15, it would look like this:
Taxable 44.6% $17518.6% Total Stock
26% Total International Stock
Roth IRAs 23.5% $92k23.5% Total Stock
TSP 31.9%$125k15% G fund and F fund
16.9% C Fund and S Fund (to make Total stock market)
However, since some of this money might be for a house (or other shorter term goal), I believe the smarter move would be to invest it all, but dial back to 70/30 or even 60/40 to account for the safer investments needed for a shorter term goal. This would still keep all of the money invested. It would grow slower than at 85/15, but probably faster than how your total is growing now.
This arrangement has two advantages.
-All of your international is in taxable where it is eligible for the foreign tax credit (see the Wiki).
-All of the international is invested in a complete fund containing all of the international market instead of just what the I Fund contains. The I Fund is missing small cap stocks and the entire emerging markets universe.
I think I Bonds are a good choice too, but you have some pretty good inflation protection if you are using the G Fund.
Regarding "investing it all", I didn't take out any for an emergency fund, but you should do that before investing what is left.