I went through similar thing in Spring. After getting kickr core and zwift now during a week all my work outs are indoors.
I have all my workouts created in TrainingPeaks and import them in to zwift. With zwift I found I can do hour and a half to two hours without issues. There is enough visual and audio stimulation not go get bored. Also with this setup I found I can push harder and have more consistent work outs. The erg mode keeps you honest. haha
As for Kikr vs kikr core. I went with the core because at the end of the day I didn't need extra features. The higher power is not really necessary. I can't hit 1500 outdoors, let alone indoors. For climbing simulation. In zwift default is 50% anyway. The kickr does have wider and theoretically more stable base, but I haven't had issues with it with core. The kickr does that have the handle which would make it moving around easier, but I leave the trainer as is and rarely move it. So not a big issue.
Also if you have a dumb trainer, try it with it. You won't get a full experience, but you will get like 90%, and as was mentioned already zwift has a free trial.