I went to Lake Balaton when backpacking about 30 years ago. Don't remember much, mainly trying to buy a train ticket from Budapest. I wanted a return but that translated as buying two tickets. It didn't amount to much money for me so I didn't realise, until the conductor on the train saw my ticket and insisted on giving me half my money back! I don't think I sampled the local confectionery - but they do look like good cycling food!
When I did my route for the TCR in 2018 (TCR 6), Lake Balaton was a big landmark. The obvious / shortest route was to go west of it but, when I looked at alternatives, I had a wow! moment when I realised that you could cut out loads of climbing (>3000m for an extra 12km distance) if you went to the east, so that was where I routed. I wasn't able to start but watched it closely and was interested in which routes people took. James, in the lead, followed almost exactly my route, and went to the east. Then, when I saw Bjorn, in chase, going to the west of it, I thought there was no way he could win from there and he couldn't have taken much care of his route. So it wasn't entirely surprising that he then came unstuck in the mountains, routing down a goat track. Interesting to see which side of the lake you routed, Jonah!
No escape from ferries! This one is smaller and more frequent so a bit lower risk - more like the Danube ferries on the original TCR route - but still an issue in picking the right one, though: you don't want to either miss yours or have half a day sitting in the terminal.
I dotwatched the 2017 race and legality of routes in Hungary was a big issue that time, too! The good thing about mandatory route is that the organisers will do all the research into banned roads. There may be a call to make if they have missed something, though.