Your testimony in court will have to satisfy the judge that you did in fact establish residency there. It won't help you that you paid in cash with no paper trail (no receipts either, I presume). The next best thing is witnesses who might have helped you to move in (who can confirm when that happened to establish dates), mail that you received there addressed to you, or a copy of your driver's license (or driver's license history) showing that as your address (which you should have because state law says you must change your driver's license within a certain timeframe of moving). Anything you have like bills or other things that show that as your address can help establish your case. Once the court is satisfied that you were a resident, that opens the door for the unlawful eviction portion of your claim. Once you show you were a resident, you have certain rights under the law, including the right to proper eviction, whether there was something in writing or not.

Your local police should be happy to standby to prevent a confrontation and ensure your safety while you gather your stuff - IF he lets you in. However, police cannot and will not force him to allow you into the residence, or to have access to get the stuff. If he says "buzz off", then that's what you'll have to do. Police can drive up and sit for a few minutes, and that's the limit of their involvement. A deputy sheriff (who is, by definition, an officer of the court) can help you accomplish the return of your items, but only when you have an order from a court, which you get by suing.

You can't stop him from talking to your employer whether he gives you the stuff back or not. If what he tells the employer is the truth, then it's the truth and you get to deal with the fallout. If it's not the truth and you suffer some sort of damages, then you sue again.