I’ve had to evict the original tenants, got rid of a roach infestation, and the electrical seems iffy.

I think there may be a market for a lower density campground that offers a higher level of privacy per site with amenities (electric/water hookups, RV dump site, bathhouses, etc...) but...

Hot water heater, furnace, gas, electrical box, HVAC, oil tank, plumbing pipes.

Basic plumbing, electrical, HVAC knowledge will go a long way.

Quote from @John Williams: I would only support this because it's California where electric cars are most likely to be mandated and used.

Here are the numbers I know so far:Rents4 units all currently occupied on one year leases- #1: 1/1 $995 monthly- #2: 1/1 $995 monthly- #3: 1/1 $995 monthly- #4: 2/1 $1,100 monthly- Gross rents: $4,085 monthlyExpenses- $12,070 taxes annually- $350 monthly insurance (my estimate, they have liability only right now)- $175 monthly landscaping- $120 water (electrical on separate meters, tenant pays)- Total expenses: $1,651 monthlyNOI around $2,434 before vacancy, maintenance, and management (although i would likely self-manage these)Property needs about $50K in other repairs and udpates from what I can see.

Storm ponds, storm drains, flood ways or flood zones, underground electric, fiberoptics, etc.On the concept plan above. 

It was quite extensive, all new electrical, hvac, plumbing as well as foundation, painting, floors and yardwork and demo of shed.

Stripped to the studs, new electrical, new plumbing, restored original wood floors, and brought a 1946 gem back to its original form!

Common concerns in pre-1940s buildings include outdated plumbing, old electrical systems, and structural issues that could be costly to bring up to modern standards.