So the weather hasn't been great over here forcing me onto the trainer. However, while I can ride hours without issues on the open road, when on the trainer my butt starts to feel it at about 30 minutes and I find it very difficult to stay on past 1 hour.

Can anyone give me some advice to make me trainer rider more enjoyable. I'd like to be able to get through a full length movie while on the bike/trainer.

Get out of the saddle more.

That's normal.

You might try a different saddle, or experimenting with shorts.

Also make sure your front wheel is raised.

And it helps to get off the trainer every 30 minutes to stretch a little bit. Sometimes I ride 30 minutes, then do some stretching and core work, then ride 30 minutes, and repeat.

Try it on rollers, then you will view the ability to move around on the trainer as a god-send. Then go back to the trainer.

+1
I dismount and do sit ups and push ups for every 15 or 20 minute interval. This practice extended my trainer endurance considerably.

+1

On the trainer I stand, even if it's just for a pedal stroke or two, maybe every 5-30 min. I can and have done 5-6 hour trainer rides, although my normal trainer rides are 1-2 hours.

Think about when you stand or unweight your saddle, like if you put your foot down at a stop sign or light, when you stand to get going from a stop or a corner where you coasted a bit, a short steep rise where you don't bother shifting, etc. Most riders stand up much more than they realize.

When you coast on the bike you may coast in a non-load bearing fashion, bike tilted to the side or something. On the trainer when riders coast they usually stay planted on the saddle.

Finally when you go hard you naturally unweight the saddle. If you're putting a lot of downforce onto the pedals you will be supporting your bodyweight just a bit. If your trainer rides are steady and not too hard then you're not going to be making those efforts and therefore you won't be unweighting your saddle a touch.

hope this helps

Ditch the movies and get some training videos (CTS, Spinervals, etc.). I can't stand mindless spinning to music or TV on the trainer but I can do long sessions when it has a clear training purpose with a coach.

You just gotta keep working at it. It improves. And when you can hold the trainer position for 30,you'll be able to hold the drops in the road for 60. Just keep at it. Consider that a lot of folks who train for the ironman triathlon routinely do 6 hours on the trainer with like almost no breaks, so HTFU!