In reply to alasdair19:
Having converted a Transit semi high and a LDV 400, now using a professinaly done Merc Sprinter loads of things to look at.,...
Plan lights elect cable points etc well before starting to line the back.
Think about putting a sun roof/ roof vent in off ebay. The bigger the better, of add more. Realy adds light/ sense of space in the back.
Easy to get seats that bolt in off ebay for the back.
Look at as many different conversions for what you would like. A seat that is also a bed makes more sense than just a bed.
Look for someone scrapping a caravan for internal bits, don't think you can salvage windows/roof vents though as they are buggers to strip out.
Check out the minium you need to do to convert to being a camper for insurance/log book purposes. Think it needs a sink now.
Insulation wise, roof insulation ok with plywood ontop. Have used bubble wrap, was easier and cleaner but potentialy not as warm.
Ventalation very important, condensation will be a major snag without really good vents, but then you need to be able to close for heat retention.
A cab heater is a luxery, nice but expense to buy and noisy to run. Better off buying a first class sleeping bag or additional duvet to throw ontop and use the vechicle heater or brew a cuppa for extra warmth.
Look at how you are going to shut the light out at the front. Use a external cover, a internal cover, curtains etc... Internal sheeting using velcro/poppers seems to be the least fuss.
Tim