Road racing is very hard to come by here in the UK too, as are crits. Many moons ago bike racing was strictly banned, so riders did time trials in secret (easy to just say you were just out for a ride and had no knowledge of anything else going on). Since then TTs have become legal on open roads but bunch racing is still a legal minefield of permits and road closures. We get quite a bit of racing on closed/private roads (motor racing circuits, old airfields etc), but proper races on public roads are few and far between.
That said, closing roads for a running race is seemingly very common, almost every town in the country seems to have at least one 10k/half/marathon a year. There’s one half marathon that I’ve done that uses a figure-8-and-a-half route (as in 3 loops, not 2), which would make for a nice road race course. The course never crosses over itself, but does use opposite sides of the same junctions a couple of times; if you did two or three goes at each loop you could get a decent distance out of it. It’s nice rolling countryside, good for a breakaway and chase. The half marathon has closures in place for a good few hours on race day and plenty of volunteers to marshall, I don’t see why it would take anything extra to make a bike race out of it.