
I've been hoping more people would chime in so I wouldn't have to, but....
It's all about the weight. The kitchen/galley will most likely be the heaviest part of your build and, chances are, if you put the galley in the back without moving the axle, you will
not make your 60/40% weight requirements. That's 60% of the weight in front of the axle and 40% behind the axle. If you have too much weight behind the axle, you will have trouble keeping the trailer towing straight behind your tow vehicle. If a tractor trailer passes you or a gust hits the side of your trailer, your trailer could start whipping from side to side and you could end up either jackknifing or rolling and possibly ruining both the trailer and the tow vehicle.
While your trailer doesn't have a cabin on it, it is easier to move the axle because you can flip the trailer so its underside is up where you can work with it and see what you're dealing with. It's also the best time to tow it to someone who could move the axle for you, without charging you a small fortune.
If you put the galley in the back and don't move the axle to compensate, you will have to really, really, really watch your weight, putting your ice chest and food and possibly kitchen kettles in the back of your tow vehicle or secured in the front part of your cabin, on the bed, and carry them to the back when you set up at camp and even that may not be enough, depending on the amount of wood you have in the back in cabinets, counter, and lifting hatch (or doors). I left my axle in the middle but my kitchen is in the front of the cabin and, still, I keep my ice chest and some of my food in the back of my tow vehicle.
Best Wishes!