Just on simple metrics, $150 per space is very low. 35% stated expense ratio is low on top of that. If you are SURE you can make ends meet that way, that gives you 20 * 150 * ,65 * 12 = $23,400 per year in net income not including the garage & house.
You need to build your own expense metrics and our banks figure $50 per lot per year for reserve, so you might take that into your expenses and also any deferred maintenance (current owner has not been doing any, right?)
And you need to make sure you can keep the park full if half your tenants leave because you [insert reason here -- raise the rent, enforce the rules, collect the rent, etc]. TEST AD.
Local housing stats concern me and low lot rent. Is there demand at lot rents that make sense (now, and in 10 years)?
What are the competitor parks doing and how will you compete with them?