Transfăgărășan, the 7C, is without a doubt the most popular road in Romania. Made famous by Top Gear. In there can be a lot of people there too.
At the summit, the north side is connected to the south side through a tunnel. Which does not open before July 1st. That said, it is sometimes possible to pass it, if weather (snow) allow, as there is a door in the gate your can squeeze the bike through.
On the south side, there’s a dam, which is worth a little break. Coming from the south, you will want to keep right, so you ride east of the lake, unless you want some gravel. In that case, you keep left, into the short tunnel. The gravel bit is 20 km. Along the gravel there’s a few camp sites. It is not recommended to wild camp as there are bears in the area.
From the dam and south, there are plenty of hotels and B&B’s.