Flanders is dead easy to do. Belgium is tiny. Loads of towns to stay in around. Ghent is a short drive to oudenarde for the sat sportive. Sunday race if you have a designated driver kwaremont is awesome. Dump vehicle on a road. Loads of beer tents, TVs and men’s and women’s races go past 5 times in total. If everyone wants to drink train can be pre booked online and is cheap to oudenarde. Watch women’s race and men’s passage through town square drinking beer. Walk over to kopenberg, it’s got a small beer and frites and a big tv. Watch men go past. See finish on tv, walk back to oudenarde and see all team buses and have more beer.
Paris Roubaix is purer as it’s the proper route for the last 80k or so but watching it is weirdly under commercialized and Dirt cheap food and beer in the velodrome which is free to get in (!). The whole of Flanders goes nuts but you get the impression the rest of roubaix aren’t really bothered. And northern France is a dump. Stay in Flanders and drive across