Not sure if his new book covers which states have exceptions to the rule but reach out to him. 

I understand as someone new to real estate investing there is a lot to learn and even though I have read many books, until I do it myself for a few years, I will be far from an expert.

The course came with PDF texts (not books) and a very lengthy excel sheet to memorize and tackle on my own.

Instead, I've heard of hosts raising the nightly rate high enough it won't book or setting a 30-day minimum stay and had no issues with a double booking.

For someone who is self managing a portfolio of rentals, any recommendation for bookkeeping books?

If it’s not a partnership or other entity then the balance is not that important, but if you’re already reconciling books and have A solid set of books it’s best to provide the balance sheet.

Quote from @Jason Seay: I address this in my book and I have an addendum in my forms package.

Any books, blog, etc where you would recommend starting to learn about these business structure etc, that are not written with the only purpose to sell you something ?

Plenty of successful multifamily investors have written books or have podcasts where you can learn a lot for almost nothing.

You can always buy the books and learn all there is if you have the time.