Build an alloy frame and attach alloy or GRP panels to it, my iveco bus is built this way.
If making a floor then use sealed fiber board and insulate before fitting a top skin, good luck.
It wont work, first once you introduce gearing you lose half the input, it must be direct drive disc with hinduminium magnets and not some old 240v genny of a petrol unit, vertical units produse much les power than horazontal ones.
Turn the stop start cr-p off and buy a normal battery, remember start stop fooks the flywheel ring gear teeth and burns out starters much faster, just more boll--ks to get our monies.
I told you about new batterys a year or more back, big problem is getting the current out of them fast enough for car use, getting there but it will be many more years, 2030 is still a long way of.
A fiesta is not a car but a unreliable skip on wheels, we had one here 30 years back, worst bit of crap ever, I see a big fight looming and im of to bed, pronto.:eek:
You cause more strain pushing a clutch diaphragm in than any drag on a layshaft doing nothing other than turning a ball race, clutch in is a old school thing that d instructors told you so you would not jump forward if started in gear.
Some places like that here, just wont sell to Joe blogs, fibre flooring springs to mind when I was rebuilding my van, ended up using marine ply clothed in GRP by me.
The cable should be under the panels, and best way through the roof is a boat deck gland, the black plastic type are good, mount it also under a panel away from sun and rain.