Truly nothing. The bike should be as ready to go as the day you wrapped up the season and put it on the trainer.

This is what I would do prior to the ride, though I would do about half of this for any outdoor ride...

• Lube the chain
• Check brake clearances (in case you knocked them while on the trainer)
• Check the wheels for trueness (same time checking for brake clearances)
  
• Check RD shifting alignment
• Pump the tires
• Check for binding in the headset from sweat while on the trainer
• Check for no play in the crankset

After the ride I would wash it well with soapy water to get rid of any sweat that may have started attacking metal bits and give it a close visual inspection at the same time. Also, pay attention for any new sounds or creaks during that first ride and correct them after the ride.

On that note - try to remember that thing you were going to look at last fall right before the weather broke and you put the bike on the trainer ;-)

Depends how meticulous you were with protecting your bike and how hard you sweat on it.

My first indoor season, after 5 months on the trainer, my sweat had fused the entire front brake and stem - couldn't even turn the handlebars, and all had to be replaced. This was with a towel on top when I used it - clearly I sweated through it.

Next season I got a bike cover, still nearly fused my brake.

After that, I always wedge a towel over the FB seems to do the trick. I will also make sure the stem isn't fused and turns correctly after bringing it out

After hearing many stories like this guy above I wrap my stem, headset cover, front brake caliper and the nearby cable housings in plastic wrap for trainer use. Then a the cycleops towel thong, then another towel to rest on top of the aero bar arm pad rest. I also put plastic wrap on the arm pads too to keep them from getting too funky. Also use a cheapo trainer wheelset for both front and rear. I know I'm sweating on the front wheel hub when in aero but isn't my nice or race wheels so I don't care it they seize a little or not.

Never had any issues with the bolts or front end seize on me yet with the same bike that that predominantly lives on the trainer for the last 4.5 year. Although I typically would it 2-4 hours of trainer sessions a week during the winter though.

But I check what was suggested and make sure things are in working order prior to riding outside (usually only for a race for me).

Every time you sweat all over your bike while on the trainer, you should think of it like you just rode through a nasty rain storm. You wouldn't ride through 5 months of rainy weather before thinking about maintenance or cleaning right?