We’ve got a T4 Westfalia conversion. It’s lovely but if I was to do a conversion from scratch I’d probably do things slightly differently.
Captain’s seats which swivel around into the van are great – mean you maximize the use of space.
Full width rock and roll bed would give you 3 seats in the back and storage behind. If you go with the VW type, there’s storage underneath too for a table and other bits.
In terms of storage I’d go for a smaller number of large lockers or units which you can easily stuff stuff into so as to leave the interior uncluttered when you’re parked up. Our Westy has loads of little nooks and crannies and a cavernous wardrobe but it’s all a bit hard to access so you only end up using about 60% of the storage space and you end up with gear strewn all over the place. If you’ve a high top, then there’s scope for some overhead storage which saves on floor space.
Go for vinyl, cork or rubber flooring – not carpet, it will get really manky.
Removable kitchen unit is a good idea if you also want to use the van for carrying stuff. Also means you’ve got the option to cook outside if the weather is nice.
Consider fitting a wet locker for drying out stuff when the weather is bad.
Eberspacher (sp?) or similar night heater is a good idea if you want to use the van all year around. With good insulation obviously.
Opening skylight or sunroof a good idea for ventilation.