My parents were living in Bulgaria, about an hour from Varna, until just before Christmas when my father died unexpectedly. I was there for about a fortnight.
There are nice places around the coast where most of the investment has taken place. As soon as you go inland by 10 minutes it’s exactly as you would imagine a poor, ex-soviet bloc, country to be. The roads are absolutely littered with holes and the bits where it’s OK is where everyone drives like a lunatic. There’s just not a lot of traffic on the road, so that’s a positive.
Bike hire will only be in the tourist towns on the coast.
Who are you flying with? WizzAir?