I spent 3 months living in my van in Spain last winter, no campsites, just aires, car parks, on the street, etc.
One way ferry booking, didn’t book return until I’d been there 1 month.
Other than that no planning at all.
No issues at all.
My only interactions with the Police in 3 months
1. Telling me I could stay on a beach car park after they moved the mass of Germans in 8m plus MHs with trailers etc.
2. Moving all vans to the edge of a Malaga stadium car park for a football match.
3. Quick look in my van on the way home in Santander ferry port for illegal migrants.
I’m sure the Daily Mail has a hotline for scare stories.