Depends a bit on how racey the road bike is. If it is a modern highly specific racer, forget about it. If it is an older steel racing bike, and even with perhaps more clearance for wider tyres, you can use it for hostelling or very light camping. In that case, a Carradice Nelson Longflap or Camper Longflap may be the most appropriate bags.
There are problems with road bikes:
Most frames are not stiff and strong enough for serious touring.
Modern road bikes lack the clearance for a tyres wider than 28 or even 25 mm without mudguards. Narrow tyres on a loaded bike have to be pumped up very very very hard.
Modern racing wheels with few spokes and fancy patterns are often not strong enough.
Geometry is nervous and uncomfortable.
Gearing is too high.
They may lack fittings for a rear carrier, although that can often be solved.
Older racing bikes often had stronger frames, more clearance, a more comfortable geometry, and fittings for a rear rack. They were more like what we now call an audax bike. If you have one of those, you can use it, provided you limit the luggage to something like 10 kg. That is possible: ultralight hikers carry less. Visit their websites for inspiration.
So if you want to go this way, and if your bike is not too racey, focus your attention on lightening your load, take a hard look at your rear wheel (perhaps get a traditional handbuilt 36 spoke rear wheel with a heavy rim), avoid anything off road, fit the widest possible touring tyres (Panaracer Pasela), get SKS raceblades for mudguards, perhaps raise your handlebar, lower your gearing somewhat.
Hope this helps. Touring is fun.
Willem