Stationary bike Vs Road Bike

Road bike with Spinervals kept me going through the winter. Then you have the best of both worlds. When it's good weather, back out on the road on the bike you're already (or still) used to using.

The only stationary bike workouts you should be doing would be your road bike on a trainer... need to train your muscles to the bike you'll be racing on.

A stand up stationary bike will not provide as adequate of training as using your actual bike. 

If you are comfortable with dialing in your position, an adjustable bike like you would use in a spin class would get you close enough, especially if you could use your bike shoes with clipless pedals.  I can get a spin bike set up so it is 95% of my road bike position for saddle height and fore and aft.  The handlebar set up is a different thing entirely but I am not concerned about my arms during a spin class.  I agree that the typical "stationary bike" isn't  going to be as appropriate.

I ride a stationary bike at hotels when I travel, which ends up being almost once a week.

It's not as good as riding on my trainer at home but not a bad second choice.  It's much better than not training.  Your position is different from on your own bike but, for the most part, you're working pretty much the same muscles.

Whether I'm on a stationary bike or on my trainer I like interval workouts like

10 min warmup
2 min hard, 3 min easy
repeat lots of times

Brian