I'm just in the middle of planning next years Euro trip.
Last year we took the overnight ferry from Hull to Rotterdam, on to Heppenheim Germany, Glarus Switzerland, Beaune France, Spa Belgium then Rotterdam home. Stunning scenery in Switzerland and driving in Europe is so straight forward.
With that you've got about 4.5 driving in between destinations. You'll need a Vignette for driving in Switzerland but you can purchase this as soon as you get over the boarder and it's only 50 quid. Also the speed cameras are on the tunnel entry so watch your speed, someone i know was relieved of his vehicle in Switzerland and the police had it for 3 months before they'd release it.
Next year is much the same but including Le Mans for the classic 24h and the Italian lakes. Debating the Southampton ferry but the trek
down south for 8:15 Am doesn't sound appealing. The cost of a southern hotel puts the cost up to the Hull / Rotterdam ferry so swings and roundabouts.
As for everything else, Hi Vis, Breathalyzer etc etc, plenty of low cost euro kits kicking about ont tinterweb.