I did my Caravelle last year, the original floor was beyond rescue and seemed to be holding water.
Anyway, I bought this sound deadening
https://www.deadening.co.uk/products/do ... t-hex-roll" onclick="window.open(this.href);return false;
Then bought some 7mm foil backed adhesive foam insultaion in a roll. The abive place sells it but I bought mine off ebay as it was slightly cheaper at the time.
Both products are a doddle to cut and fit, also made a big improvement on noise reduction and insulation.
For the floor I used the same products but I've also put down 9mm ply and carpet.
When I converted my panel van I used flash band and foil insulation from wickes. It worked pretty well but I think what I have now is better.