Take the advice from @Nathan Gesner and @Bud Gaffney and learn as much as possible BEFORE buying RE.

One of my friend happens to be a RE agent, landlord and a property manager himself and he seems to feel that as long as she pays rent on time and does not create nuisance, not to worry much and just keep do a quarterly property inspection.

Use your RE background and make sure zoning allows and there are no hidden grandfathered requirement if it switches use.Sounds like you have the $600,000.  

Kind of like a cash for keyshttps://martinezlawcenter.com/new-rental-laws-in-california-...Most of the long time investors I know haven't had problems but if you get a "professional tenant" in look out and call your RE attorney.  

None to be recommended.They are all alike.Have to get refunded for my fees and it has been more than a year and still have to taggle for them to re-issue me another check.They are very sloppy.

Can I research comparable sold properties in RE Simpli?

The best deal I can find today is one that you buy cash, invest a rehab and when you pull out 75% of your ARV you leave maybe a small amount of money in the deal and you break even (BEFORE DISCOUNTING FOR VACANCY, REPAIRS, etc) Yes that means you leave like 10-25k in the deal and your payment becomes $3000/m and your rent is $3000 a month or slightly less.This is for my local market and for Class B or higher RE. 

If you set it up well, don't worry, you'll get guests when you repost.If you really want to capture the existing bookings, then go for it and plan to re-furnish it at the start of slow season.

and if you're re-financing after rehab, can you do it via another DSCR?

Your tenants obligation was to pay you on Jan 1, so it doesn't matter if they paid someone else they still owe you...obviously details re: notice and dates all come into play here and from a practical perspective I'd work with the tenant and not move to evict over this.