Romania itinerary feedback

Plan to spend 3 months slow traveling around Romania this summer. I've mostly finalized my itinerary but still fine tuning a few things and thought i'd ask for some feedback here. Here is the rough itinerary.

Flying into Bucharest and then immediately flying to Timisoara to start my travels there. Since i'm starting mid July the plan is to start in the north where it's cooler and then end up back in Bucharest when it has cooled down in the Fall.

July 15 - Aug 13 : 4 nights in Timisoara, 3 nights in Oradea, 1 week in Cluj, 3 nights in Sighisoara, 2 weeks in Sibiu
Aug 14 - Sep 10 : 1 month in Brasov
Sep 11 - Oct 9 : 1 month in Bucharest

The 1 month in Bucharest may be a bit odd but it is a personal choice. Also the 1 month in Brasov is fixed in my plans.

I am mostly looking for great hiking opportunities since I am an outdoor enthusiast, however the issue is I don't have a car and unfortunately I don't have my IDP at the moment and it looks like that is necessary to rent a car in Romania and getting one via the AAA shipped international is a pretty convoluted process and the other options are not only shady but ridiculously expensive ($150+) so the gist of it is that I will be relying on public transport.

Given this info, am I making the right decision to spend 2 weeks in Sibiu or should I spend more time in Cluj or other areas? The reason I am on the fence here is that I have heard public transport into the Fagaras mountains is hit or miss but I also hear that there are options to hike in the Cindrel mountains that are well connected. Also perhaps better hiking near Sibiu itself?

Cluj has the Apuseni mountains but not sure if the hiking opportunities are as impressive as Sibiu. Thoughts?