Wow, without even actually trying too hard I got Megalopolis! I don't think I've ever done it without cheating. I was using river map 825B.
The transportation maintenance is a bug/feature of this version of the game. Normally if unfunded roads or rails deteriorate and randomly turn into rubble. But this version, whether intentional or not, when you use a road/rail+powerline, it won't deteriorate at all. So I can use all rail as long as I overlay power lines over them, and they won't deteriorate. #gameing
Oh, and I had an imbalanced profitable budget for nearly 150 years! Ended up with $300,000 cash on hand, and at a low tax rate of 2%.
I accomplished this by not paying any transportation maintenance, having few police, and only one fire station.