Romania with toddlers

[whatsagoodusername]

We are going to Romania in July for a wedding for a week.

We have two DSs, aged 3 and 4. We will be in Bucharest for the wedding for three days, then have 4-5 days to explore. The child free friends are going to the Danube Delta, but it doesn't look like it would interest our DC for long.

Any suggestions on what to do that is child-friendly? They love trains and castles, so we will probably head to Transylvania at least for a bit.

Thanks!

Any suggestions? Thanks!

4-5 days to explore is not much the transportation system is extremely slow wether it is by car (will you have one?) or train.
July will be 30-40 C in Bucharest. Transylvania is good idea. Brasov, Bran, Sinaia, Sibiu, Sigisoara, it will be a bit cooler. You could take a plane to the North or Timisoara.
In Bucharest almost all museum are children friendly the village museum, the peasant museum and the natural history museum. The parks are great for children Herastrau, Kiseleff, Cismigu... Travel by metro to escape the heat, cheap and quick, don't take a stroller, be extremely careful of the drivers, potholes, don't trust the lights or the one way direction on the road (the traffic is insane nobody seems to respect it)
Avoid travelling/sight seeing between 11 and 15, it can really heat up in the sun.
"Carturesti" at piata romana, is a great place to have a limonada or lunch with the kids and explore the shop.
Danube delta in July is madness. It is also really remote. You would need a very good travel insurance for the children, a friend of mine had her toddler extracted by speedboat then helicopter or plane to the nearest hospital!