How did you make the tunnels?

@homodetritus:
The wheels are the ones that appear when you put a lift section and set it to friction wheels. I usually like to put transport sections for the pre-lift, but the friction wheels on lift sections are much closer together that the ones on the transport sections

@<iSatNav>:
Pretty much just searching online. There are decent quality free ones out there, but don't expect great looking ones like the ones Dave uses on his coasters (Air, The Big One) without paying.

Any where does one get a skybox like that?

Thanks!

The tunnel was made using another coaster. As for the connectors, I was planning on doing that, however I couldn't get them looking right, so I decided just to leave them off for the time being.

There is some nice B&M shaping going on here, very well designed. As you already said it isn't 100 % spot on, but I'd say at least 90 % which is still amazingly good. The custom environment makes this coaster shine even a bit more (no pun intended).

Just a few things I've noticed, some of them probably quite nit-picky:
1. Some supports seem to miss flanges, e. g. the ones on the lift and the loop.
2. Try to make some custom B&M loop connectors, they are worth the effort. Right now it looks a little weird.
3. The position of the sun doesn't match the shadows. Don't know if rotating the skybox would fix this issue.
4. The tunnel sound when a train passes the trenches could have been avoided if you created the invisible tunnel by using another coaster.

Keep up the good work! :)