Ok since no one was able to help me out on this one, I just went ahead and tried it out. I used a mix of fir and peat moss for the background. I bought it already pre-mixed so I just needed to add the glue and the water. I then applied it to the background and let it sit for a couple days to harden and cure.
After thoroughly washing everything I then put the background in the tank along with the waterfall and the fogger. I set everything into place and used rocks in the pond area to help the guy get out when he gets in the water. I also used a matting to go over the eggcrate to stop dirt from going through. I got this at one of my jobs. I used zip ties to hold it into place to the eggcrate so that it would not get moved around by the dumpy.
Now onto the substrate. For this I used a mix of the fir and peatmoss I used for the background as well as a brick of Exo Terra forest moss. Threw it into a bucket with some water and let it sit for 15-20mins and then stirred it to remove clumps.
Put the water in the tank first and then put in the substrate, and turned on the waterfall and fogger. I also added in some accessories for the guy to climb around on, plus there is a ledge above the cave/hide I made as well.
Pic of the left side looking into the tank.
Pic of the right side looking into the tank. I have the fogger and the pumped blocked off with rocks so he will not get a shock.
Here is a shot of the tank from above.
And finally here is a shot of the tank from the front.
So I am going to leave this for about a week or so to let everything settle properly, and I want to monitor the temps and the humidity level before getting the dumpy. I also need to get a screen cover for the top to stop the guy from getting out.