It's actually remarkable easy for a level with straight terrain like this one. All you have to do is place a bunch of terrain pieces to cover up the required area, and then go over the unneeded bits with eraser blocks. Like I said, it's useful to refer to the x-y coordinates to make sure everything is in the right place. The screen-start viewer helps with the initial terrain placement too.
If you want a really easy one to try yourself, you could do "Tightrope City".
Other small levels with nothing but straight terrain aren't going to be much harder than this - they'll just take longer.