100m and I'm going the other way. I'd choose a midling city surrounded by the usual huge swaths of unincorporated land you find outside the metro bubble. Cities expand their city limits by annexation regularly as it is.
I'm going to do what every other wealthy person does and influence the system. I'll push new laws through these puppet legislative branches and gradually expand my city. In the meantime, I'm playing real life Sims by building a City tailored to my desires. People struggle to balance renovations on their homes because of the options and details involved, I'll never be bored with the challenges of crafting a City.
By the time I'm dead I'll have a lineage with tendrils throughout the State, Country, and globe that will be historic.