What do you use for bookkeeping, accounting and filing taxes, as you start up?

The owner typically pays this as part of ownership, just like taxes and insurance.

Is there a tax strategy for using capital gains off the sale of a home to pay off other homes in your portfolio to improve cashflow?

Not worth it from a cash flow perspective, and most of the investors I work with also avoid condos for the same reason! 

Just keeping things separate for now will be a big help come tax timeGood luck

Second, I received a request from State Farm today: Please provide the gross sales/receipts amount for the insured location(s) as reflected on their most recently completed tax filing or anticipated gross sales for the upcoming fiscal year.This strikes me as a little weird and perhaps I shouldn't jump to the conclusion that this info will be used against us (and result in a higher premium).

The bill that includes the extension of 100% bonus depreciation, Tax Relief for American Families and Workers Act,” H.R. 7024, was not included in H.R.3935. 

BEFORE taxes and insurance, probably common utilities and maybe an employee or two?

Assumed purchase price at asking, got the rent roll from the listing agent, currently rented 0% vacancy, and made some assumptions on taxes, owner paid utilities, etc.

Got this note from VRBO today:Dear Partner, We are writing to inform you that effective July 1, 2024, California Assembly Bill 537 will prohibit advertising, displaying or offering a rate that does not include all fees or charges required to stay at a short-term lodging (except taxes and fees imposed by a government on the stay).