I'm a minimalist, on the road, so look to the "old timers" on here for the real professional ways to make your "professional camping" the most comfortable it possibly can.
BUT, if you NEED to get rolling in it ASAP and add features as possible....
BUNK. You need a bunk!! And remember that it must be comfortable. If your bunk is not comfortable you will not be rested, and that is the absolute worst way to the in this business. I built a fold down bunk on the front end driver side of my cargo area and attached it directly to the wall. My van is not insulated so that made attaching it to the wall supports easy. 2x4s, a sheet of thick MDF, some household door hinges & long screws to hold it in place. Look back at postings I made or pictures I posted from late 2012 for easy ideas. What I keep on my bunk for comfort is two furniture pads folded in half, an air mattress I got from Walmart, a twin size comforter folded in half on top of the air mattress, a heated mattress, a twin size fitted sheet, a "20 degree" cocoon type sleeping bag & a pillow.
HEAT. You need to heat!! Trust me, I have tried and tried to justify having my generator and electric heater and will tell you that it is not easy. Refilling gas tanks at three in the morning in 10° weather sucks! But my wonderful wife bought me the generator for my birthday and it's not like I can say "sorry honey".
See BillG27's posts about his Espar gas furnace. This may be the single most important expenditure for you keeping your sanity. Yes that sounds dramatic but to be able to flip a switch and have as much heat as you could possibly want sounds quite comforting to me. And to be able to run it off your vans gasoline tank is priceless. It's not cheap, at $1400 plus install, but you would spend as much on a Honda generator, a heater & has to run them over time. Just look into it. And talk to Bill too. He's a great guy!!
CARGO SECUREMENT. Yes. Need straps. As for e-track, ideally you have enough but not overkill. Many of these guys have so much etrack that their cargo area looks like an etrack store. That's not me. And my bunk keeps me from placing it on the front 6' of the left side. Another possible reason to reconsider bunk placement. I usually have to sling the strap from that six-foot point, up around the front of the skids and then back to the right side where I can secure. Floor track would be much easier, I imagine, but see somebody else for better load securement ideas me.
EXHAUST FAN. I did a summer without an exhaust fan and will tell you this is a real necessity in my opinion. Laredo and El Paso are no fun in the summer without airflow. I installed a Fantastic-Fan in April or May and posted some pictures, but many people have and can advise as well. Many options to choose from and you can spend just as about as much as you want to or don't want to. I ended up with the 5000 and don't regret it.
GENSET. if you want to be able to sit around and burn power you're going to need a generator. If you want to be able to sit around and burn power without a generator you're going to need house batteries. This entire. Could be your most expensive venture. See Turtle for all things electrical. I don't know the guy, but it's not hard to tell he's quite experienced and will actually research and post a lot of useful info. You could search for the same information but 90% of it would not apply to what you're trying to do. Applying that electrical information to professional camping is the hardest part. But opinions are like a holes, and everyone has one.
As for the generator, there are two schools of thought. Honda 2000 is about $1000 and a great generator for doing this. Most of the time to thousand watts with the plenty of power. Especially if it is mainly just recharging your house batteries. The other school of thought is take that thousand dollars and only spent a fraction of it on a cheap Chinese made generator with a one-year warranty. Go to Harbor freight and see what they have. I have heard prices as low as $150. If that's really the case, that is simple math to figure out. Mine is a Hyundai Hy2000si. Birthday present. It does a good job for what I need it to do. Was also only about $470 I think.
I'll shut up now and let other people post. These people are way more experienced than I ever will be at "rolling can camping" and their opinions are all valuable. Just remember that an opinion is ONLY that. It is not a rule.