Getting back to Environment Art

I have decided it's time to "sharpen the saw" or make sure my skills are up to scratch. I've been working very successfully as a lead and art director for a while now but I miss making environment art. So this is my first step in getting back into it and spending my free time making digital art.

I need to know what to work on, then make sure I have the software required, come up with an idea or two and start building it.

A) What do I need to work on? There's a bunch of skills I'd like to hone and demonstrate on my out of date portfolio.

1. Physically based materials. I know these inside out but I don't really have any portfolio pieces that demonstrate them.
2. Hard surface modelling. Some good old sci-fi corridor, gun, armour or machine would do the trick
3. Sculpting. It's been a while since I used Z-Brush, would be good to get some sculpted surfaces in a scene.
4. Substance Designer. I haven't had a chance to use this yet but I know it's power. Looking forward to this for some tiling materials!
5. Substance Painter. I want to use this so bad. Just need some props to work on.
6. Unreal. I want to learn blueprints and lighting set-up in Unreal as it's awesome.

B) Software?

1. Unreal 4 for rendering (might try Marmoset too)
2. 3DS Max 2016 for hard surface
3. Z-Brush for da sculptz
4. Substance Designer and Painter
5. Photoshop for paintovers and for whatever I can't do in Substance yet - work copy
6. x-normal/Knald for baking