Hey smitty. The amount a peloton trainer would cost you could buy an old tt bike on ebay and a new trainer and replicate your position on it if you want to keep your race steed fresh... personally use my tt bike on the trainer all the time with no ill effect so far.

As for trainer recomendations depends on budget. Best bang for your buck probs a kickr core. I have an elite direto that i love but got it before the kickr core was available.

Finally yes you could get fitness from spinning. Wouldnt be optimal as has been said above but still builds that engine way better than doing nothing.

Nb CV is a 4:54 bike split ironman italy on my p2 (bae)