For every Park Owned Home you will need to inspect and understand the current market value. For me that means what can I sell it for as it sits today. Find someone who knows mobile home issues, construction (if you do not) to get comfortable. If there are 10 homes and their aggregate market value is 50K, then I will add that to my calculated price if I did not own any of the homes.
Only other advice would to be to have a gameplan how you want to handle them post-purchase, keeping POH versus TOH. They both affect your bottom line and effort in different ways.
There are a lot of posts you can find on the forum on these topics, and also the MHU Home Study Course covers it as well. Good luck!