If I’m doing a 45min Sufferfest Workout but have 1hr30 to spare … am I best?
Riding Z2 Endurance before the workout
Riding Z2 Endurance after the workout
Forgetting about riding Z2 for short periods
Combine it with a run instead (I’m a triathlete)
Long scream + Extra Shot + Half is Easy. You can thank me later.
Well played, sir.
So, I would say just do whatever you enjoy. We get so focused on training, on reaching goals, achieving results, that too often we forget to enjoy the journey. Have fun for 1 1/2 hours. Or follow my previous recommendation. 
it’s good training for a knighthood. Turn down the intensity as needed.
Depends on your target event and periodization, but generally speaking, I’d hit the intervals early in the session while you’re strong and follow it with the easy riding while you’re fatigued. A 10-15 mins brick run after all that never hurts, too.
That all being said, just because you have the time to spare doesn’t mean that you should fill it with more training. If you can, use that extra time to get more sleep, prepare a healthy meal or snacks, foam roll, clean your bike, etc… you’ll probably get more bang for the buck.
I personally like @jfc 's response. I don’t know how many times I’ve told an athlete that you don’t have to fill all of your available time with training. Use the time wisely- whatever that means to do. Adding a bit of Z2 riding after intervals is a good cooldown, and I’ll never say that a brick run is a bad idea for a triathlete. Even if it’s at an easy pace.
Starting with a yoga or movement prep routine to get the muscles activated and properly prepared for a session is a good use of time, as is finishing with one to cool down and help the body recover. Of course anything else you can do to help yourself have a great session or recover from it (sleep, nutrition, etc) is wise and can help reduce overall stress. It never hurts to experiment to see what helps you personally perform the best, since everyone is different. And remember that quality is usually more important than quantity, and often times it’s the little things like good activation and recovery routines, that can make us exponentially better!
I like these suggestions … well I like the first two, Half is Easy is just unnecessarily cruel after a tough session 
I agree to some extent with enjoy what you do but I’m keen to push my performance in this moment so bang for buck is important too!
@jfc and @Coach.Suzie.S thanks for your thoughts. With work and young kids I’m time limited to around 7hrs a week total at the moment so I like to maximise any training time possible … the extras of recovery, diet etc are more easily done with the kids than workouts so I try squeeze them into life!
I’ll go with the mindset of hitting the hard intervals on fresh legs with extra mileage tagged onto the end and with races approaching try to make that a short brick run more often than it is currently!
On with the suffering 