Using the TSP for the stock portion of your PP

[beafet]

If you have access to the TSP, you can use the funds within it for your stock portion.

The C fund tracks the S & P 500 index.
The S fund tracks the Wilshire 4500 (or the Wilshire 5000, minus the S & P 500)
The I fund tracks the MSCI EAFE index (Europe, Australia, and Far East)

So, to get a fairly accurate representation of the total US stock market, you could combine the C and S funds at a 4:1 ratio.

The expense fees vary, but in 2010 they were 0.025%