Heather Kay
Western Thunderer
I was surprised to realise that the coach was fully painted/lined while still in bits
It's actually suggested in the instructions that you do this. I know! Who reads instructions?!
You could paint and line the sides before fitting the roof, and leave the glazing out. Masking out the interior might be achievable with that wet tissue routine or tape. Leaving everything flatpack, though, makes it so much easier.