I can think of a couple people here who might disagree with me, but here goes.

You can do all of the models, calculations, bootstrapping, backward induction,etc etc etc The fact is that most of them are not going to be more accurate than the current yield.

So, in short, your current yield is the best estimate of future yield. Now with TIPS you are relying on the BLS' calculations, but looking at the long term TIPS and the market is pricing in a similar inflation estimate.