CA Real Estate Attorney - Advice!

[Sharyn Umaña-Angers]

I have a SFH rental property. In January, we informed the tenant (a "friend" of ours) that we were going to sell the house. I then sent someone out to appraise it, who said the house was "appalling." Since then, our tenant has not returned calls, texts, or emails, and has apparently got a job in a new city. The house does not appear to be occupied at the moment (i.e. full mailbox), or perhaps he is only returning home on weekends. But he still owes 2 months rent. He did, however, give my appraiser a key to the house. We need to get inside to clean up, do repairs, and prepare the house to be sold. My question is the legality of entering the property -- even though we are the owners of the house, and the tenant gave us a key and verbal permission to enter, California is not a landlord-friendly state. The situation could backfire on us. What does the law say we are allowed to do as far as entering the property? Would getting his permission in writing be sufficient?