If your 44W is anything like our 45A, that raised portion is the slideout floor. You can't cut part of that away or else you'll be looking at the grass when you extend the slideout.
I have a desk in our similar slideout that is built into the entertainment center with fireplace and 50" televator TV. The actual desk area has a keyboard tray on ball bearing slides that is mounted beneath the desk top. When I use the area as a desk the chair just sets on the tiled floor and everything is right at the correct reach. When done using the desk, or when traveling, I just push the keyboard tray in and set the chair up on the carpeted area. Originally I had a leather officer chair on wheels, which I had to strap in when travelling but it wasn't that comfortable. But neither were the dinette chairs so I replaced the dinette and office chairs with three nice comfortable Amish built ones from Weaver's Furniture in Shipshewana. Note that this photo is an earlier photo using one of the folding dinette chairs, which are now long gone, rather than the Amish dinette chair.