Hey!
Welcome to the site.
I'd start in
Germany adn work your way up to Amsterdam, then through
belgium (Antwerp is pretty cool) and then to Paris - From there you can take the EuroStar train through the chunnel to the
UK and do your work thing.
Your best bet for finding under-the-table type work is probably at hostels and pubs. But your best bet is to try and get that working holiday visa, that'll open up a bunch more options.
Good luck! It'll be a great trip - one I've done a few times, and keep going back for more of
