Regarding the car insurance coverage, if you're looking into umbrella insurance or general liability insurance you may be required to carry a higher auto policy like yours. I went through getting my insurance updated last month and I was required to have a 300/300/100 coverage or higher depending on the company supplying the umbrella insurance quote.
That being said, I did have the minimum needed for state coverage for years, but I am only one anecdote. The difference in premium was only about $50 a year when I upped my coverage because I carry a $1000 deductible (I also switched auto insurance companies as well). That's probably due to your contact in the industry's experience of high claims being a rare event.
Also, the amount your driving perhaps there is no need for a vehicle and you can get by with a rental? Also, who knows, perhaps in 15 or 16 years when your child starts driving there will be an insurance surcharge for manually driven vehicles due to autonomous tech.