I'm planning my long ride this July to be from Barçelona to Amsterdam via Leysin in Switzerland. I might take the train out of Barça and start riding from Puigcerda, then seven days across France and a little bit of Switzerland. Leysin is half way up an Alp so I plan to take the mountain railway for the last 15k.
Rest & Relaxation in Leysin with some mates for three days, then off again through France, maybe Luxembourg, Belgium and into Holland to arrive chez Jay & Mascha in Amsterdam another seven days later.
If you still think in miles, it's about 1,000
(or in kilometers a bit further ;-)