Answer: First things first. If you simply want to get rid of Kris, you can immediately serve him with a no-cause eviction notice. Since it seems like he has been there far longer than a year, Oregon law requires a 60-day notice to evict. MHCO form 43 C is the form for you.
The "reasonable accommodation" request does raise a potential retaliation defense, however, so don't be too quick to ruin the holidays with an eviction notice. It would probably be best to give Kris a reasonable accommodation request form (MHCO Form 15). That form requires Kris to give the park information about his disability and get a medical provider or other specialist to sign off on the fact that he actually needs an accommodation. Assuming Kris returns the completed form, go ahead and do background checks on his guests (conduct and criminal check only, not credit history). If everything checks out, have his guests sign a temporary occupancy agreement (MHCO Form 25).
The reindeers are definitely a problem. If you're okay with them being there, have Kris fill out a pet agreement (MHCO Form 21). If you want the beasts out, you can give a 10-day pet notice forcing Kris to remove Rudolph and Co. if the herd is capable of causing damage to persons or property. (MHCO doesn'thave this particular form, so contact attorney Lionel Hutz at "I can't Believe It's a Law Firm!" in Springfield.)
The parking is easy to remedy if you have clearly posted signs stating that street parking is not allowed and unlawfully parked vehicles are subject to tow. You should also have local towing company signs posted. If you fit these requirements, call the tow company and they will put that eyesore in the impound lot.
The wild card here is if Kris happens to break into your park office and leaves a lump of coal in your stocking. If you can prove it was him, you could likely issue a 24-hour eviction notice for either substantial damage to the premises if he breaks the chimney, or perhaps for outrageous behavior for forcing his way into the building. And, if Kris instead happens to leave you presents that cause your heart to grow 3 sizes, you can probably get him with a 24-hour notice for inflicting substantial personal injury.
Happy Holidays to All!