Unlike the Nissan-powered racing cars that compete in the Le Mans 24 Hours, our driver change for the next stage of Autocar's endurance trip around Europe was somewhat more leisurely yesterday.

I flew into Budapest on Friday evening to take over behind the wheel for the rest of the trip, and Mark Tisshaw left for the airport early on Saturday morning. Snapper Stan Papior, consummate professional that he is, is on board for the duration of this Qashqai journey. The pair were still on speaking terms when I arrived, which bodes well for the week ahead and says a lot about the Nissan Qashqai's docility as long-distance transport.

There wasn't much time to play myself in gently, because yesterday was a long day in the saddle.

We had to put in some serious miles – at least 500 in total – in order to reach Bulgaria and ensure we were within realistic reach of Istanbul, the apex of this adventure, this morning.

I was a little sad to leave Budapest behind, because my few hours in the city suggested it is a magnificent place. Like all cities, the Hungarian capital can't escape the build-up of pollution caused by too many vehicles on its streets, but the authorities there have an interesting technique for controlling it.

If pollution levels spike above a certain level on two consecutive days, the most polluting vehicles – which have to carry special 'environmental plates' are forbidden from entering the city.

The Qashqai's satnav suggested travelling through Serbia made for the quickest route to Sofia, our halt for Saturday night. So we made quick progress south through the grey, flat expanses of Hungary to the border.

The Serbian border officials waved us through quickly (one was making a phone call, the other was about to tuck into his lunch, so we quickly realised where we were on their priority list).

Shock number one was the drop in the quality of the road surfaces, although they improved dramatically as we approached major population centres. Another surprise were the regular signs warning us of upcoming toll booths – only for us to discover that many of the booths hadn't yet been built. 

Our first stop was Novi Sad, Serbia's second city behind Belgrade. We were interested to note that Novi Sad is twinned with both Norwich and Modena – two cities with keen car making cultures. Seemed like a good omen for our stop there

We passed a bustling open-air Saturday afternoon market and negotiated our first horse and cart of the trip on our route to the modern part of the city. Then there was a real treat; we crossed the broad Danube river and stumbled upon the old part of the city.

We stopped for coffee at the Petrovaradin Fortress, the second oldest fortress in the world. Although most of the walls are long-since overgrown, you can still trace the clear outlines of the fortifications. Better still, you can drive right to the top and imagine the various waves of invaders the place had resisted, dating way back to the Bronze Age.

Pressing on, we briefly stopped in Belgrade. Snapper Stan, who has an eye for these things, noted the daunting abundance of stark grey concrete buildings, as if the communist town planners had really sunk their teeth into the city. Nevertheless, Belgrade still has some achingly pretty areas, not least Kalemegdan Park on a hill overlooking the city and the Park of Friendship on the opposite side of the Sava river. It was sad to see some adventurous architecture, such as the striking Museum of Contemporary Art down by the river, fenced off from public enjoyment and seemingly decaying.