Paul,
Don't know where you live, but consider a track day if they're available. I'm pretty fortunate in that a bunch of different tracks in my area run them and you can ton up on a few of the longer straights quite easily.
Back in the bad old days, we all did the ton on public roads but I wouldn't now - traffic, bad drivers, road cameras, the potential for licence loss, fines and epic insurance rate increases have slowed me down.
Years ago I had one public road in my area that was suitable for such things - did 180 kph on it one time but couldn't get into top gear on it even then (too short). The area has gotten built up since then and I'd probably get killed by some soccer mom backing her minivan out of her driveway without looking first, if I attempted such a stunt today.
Can't believe how bad cage drivers have gotten over the years.
Take care out there.
Pat