TIP should return 1-2% above inflation as long as the FED does not raise rates. TIP is reported to move 8% lower for every 1% rise in the FED rate but right now the underlying treasuries are moving up with the CPI. The FED is not expected to raise rates until after November elections.
Also, if you are comfortable selling covered calls you can further improve your return. In any case you should easily outperform a CD without getting locked in.
As to timing - I would recommend that you wait 1 week. We are near the end of the current dividend period and there has been a run-up. Chances are good that you can pick up shares of TIP at a price that will more than compensate you for missing the dividend.