As far as Europe--I don't think you have a prayer as OALs during the summer. DL has warnings already posted for employees/buddy pass riders for several cities. July is as problematic as you can get. I certainly would NOT commit to organized travel with standby--anywhere in EU. Tour de France? ACK--fuhgedabowdit. Why not shoot for Formula One or FIFA or Olympics or a Coronation? Just being practical and telling it like it is.
We had a forum member hoping to get back from Europe summer 2 yrs ago and she had to buy 2 OW tkts for a few thousand bucks.
My husband won't even travel in summer to MOST countries on standby and we have 26 yrs seniority. We typically wait until end Sept thru early Nov for popular destinations. Consider holidays and events in a region, prior to planning, as well.
Please keep asking questions. We promise to use a velvet glove when trying to smack some sense into you! hahaha This is the right place.