Purchased a 4-Unit in Delray Beach, FL last July with HM (Lending On- they have been excellent)  $520K pp w/25% down- gut rehab with my own cash- now a weekly vaca rental/short term stay lux compound (www.lavidadelray.com). 

Stay on top of how they are doing with your income and expenses and know what you expect.I am a little concerned about California and what i see on television. 

Does that usually stay the same?

I've already told my tenant a new lease will becoming if they choose to stay.

A lot of our corporate guests stay 1-3 months.

Usually if the tenant stays past the lease date you cannot just change the locks

If you do I would love to hear it.Sell your ability to stay focused during stressful situations.

I've been extremely lucky and renters have stayed for many years, the longest is a family who has rented a home for 11 years. 

I am in a similar situation as you where I do want to add value and also have a place for my out of town family/friends to stay when the visit.

So as rents historically increase but your mortgage stays the same these deals get more and more profitable.