I use some scatter terrain I have to help fill in the Deathworld stuff. I have those extra genestealer infestation nodes as decoration. I also have some resin craters that allow a single model cover. Additionally, I use the crates, the Sector Mechanicus hatch and some other random stuff to mostly just make the board fill more dense. The photo in the spoiler tag has a lot of this in it.
For the photo I have things closer than I usually would, but the general idea is there. I have three sets of Kill Team terrain (Sector Imperialus, Sector Mechanicus and Deathworld Forest) so I don't mind so much a single level board with the Deathworld Forest as a change of pace. I do like to have the house rule that models can't shoot through two pieces of Forest terrain. This is mostly to speed up game play as to not spend a lot of time trying to prevent or gain
LOS. Works fine enough as it still offer
LOS blocking, but it is fairly rare that melee get charges outside of
LOS.