In reply to markmywords:
Yet to find out if insulation stops the van heating up in Alps summer, but i can 100% say for sure that a white van is a hell of a lot cooler in the alpine sun than a dark blue one!!!
Insulation definitely improves sound proofing - both from inside to outside, and from road when driving. Acoustic 4way stretch carpet is also ideal.
Additional weight for natetan's one is probably quite high as he's gone all out on it in terms of wood panelling etc. If you use a combination of cheap thin ply where possible and expensive lightweight furniture ply where needed, including sink, hob, gas, fixtures and fittings, R&R bed etc you're prob looking at an extra 200kg all in. If you add a big fresh and waste water tank, an extra 50kg easy. Will defo feel the difference to a bare panel van if it's a small van, but it shouldn't effect your handling too much, though will add a bit to your fuel costs. Check your van MAM's etc - most big vans are designed to carry upwards of a tonne so a couple hundred kg's of conversion are no hassle for them! Wee van with wee engine and a heavy conversion may be a different story though...
Solar panels are always working, always charging, and silently, without follow on costs. They won't screw your alternator like normal leisure batteries on a split charge can. If an engine based leisure battery runs flat you need to start engine/go for a journey to recharge it - kinda defeats the purpose!