Help - what else haven't we thought about...

We used to have a small storage tent to keep the "overflow" in,we also had a small waste container to save trips to the emptying point and a watering can to keep the fresh water and toilet flush topped up, you could have a Diana rack and box on one of the rear doors but then that increases the length and if not care full could "stress "the rear door hinges

Some people put a rack on the back and use a Fiamma box to put "stuff" in. We've been lucky with good storage in our small vans but we have thought of putting a box on the back as things like the large Milenco ramps take up quite a bit of space. We sometimes leave an unplugged cable on site but tend to pack most things up, we've learnt not to unpack too much and travel as light as possible.

Ps a set of windsreen covers are a good investment to help keep it cool in summer and warmer in winter also will keep codensation of cab windows down

Lack of outside lockers does come as a bit of a shock. We have a small cupboard by the door where the toilet chemicals are stored. 

Wedges, hose, tools and extra length EHU cable etc travel under a bunk and, after altering the access arrangements, can be accessed via the rear door. We also carry two collapsible buckets there. One reserved for fresh in the unlikely event of not being within reach of a tap and the other for draining grey waste if we can’t reach a drain and for windscreen cleaning. This part of the underbunk storage is partitioned off from the rest where spare towels, dirty laundry and so on travel. The frequently used EHU cable travels on the van floor in a circular bag. Once on site, the bag goes in the cab. If we’re taking folding chairs, they travel on the bike rack. 

We try to keep the van floor as uncluttered as possible and also prefer not to leave stuff, other than the cable, on site if we go out. 

Shelves fitted to the overhead lockers made a terrific difference to storage and we can now easily fit clothes for two weeks for two of us in them. Our wardrobe is a joke being full with just two jackets in it. 

It’s surprising the nooks and crannies you find which can hold a pair of shoes or a small box of tools. The cab door pockets hold a lot and you might find storage space under the cab seats. 

Do you carry a drinking water bottle and waste bin? Ours travel on the washroom floor and sit between the cab seats on site. 

You need to unlearn 40 years of caravanning if you can Travel light, in a panel van, there's no need for water containers or waste masters, just a decent hosepipe, selection of tap fittings, a fold up bucket, and a length of pipe to use to guide waste grey water into hedge rows with permission. Ramps will take up most room, but once on site they are outside, and we always leave ours, along with unhooked cable unless we are moving on. Our little MH does have external lockers, so ramps hosepipe go in there. Look at space behind seats when travelling? Or bottom cupboard under sink? 

Use a wash up bowl in sink for doing pots, keeps all bits from going down pipework, just dump bowl water after use. Can highly recommend external screens for warmth in Winter, cool in Summer and less steaming up!

As brue says, you could look into a Fiamma box, we have one, fits on bike rack, but it is box or bikes. Tend to use it more in Winter, but we do have two dogs as well, so a lot of their stuff goes in there. We put a couple of fold up chairs in there as well.

Happy hunting. At least you are not plunging into buying, but going about it sensibly. 

No windscreen cover for us, not everyone has them. 

 Just one thing that a lot do not realise is as others have also stated you will have less space a six mtr PVC is not a six metre caravan and if the front seats also do not swival round you could be looking at four metre or less "living" space

Yes, we realise that.  Our first van was an 11'3" 5 berth Trophy so we have had small environments before!

Hope you enjoy it as much as we have enjoyed ours, good luck with all your plans. 

Just noted what you have now by your avatar-