Sounds like a fun one - here's how I would value it:
28 occupied Tenant Owned Homes (TOW) * 345 Lot Rent * 60 (multiplier used for a 12 CAP rate and approximately 40% expense ratio due to low occupancy) = ~580K
I would then add a reasonable amount for each of the homes ready to go based on what you would sell them to a qualified tenant for. With the strong demand I would look for cash buyers ideally using CL, bandit signs, postlets, etc. If you can get 5-10K for each of these then would assign them each a value like that. For the purposes of this thread let's just say 10K for each - which is 100K.
For the 35 trailers that need repair I would pay maybe 2-5K per home maximum. Let's say 2K blended rate. You should argue some may need to be hauled off or thrown in a dumpster so that costs money and eats into the equation. 35 homes * 2K each = 70K
Get a good estimate to fix the major water leaks and other infrastructure repairs and bake that into price. If it costs 25K to fix those then subtract it from the price.
580K + 100K + 70K - 25K = 725K
One other thing. Considering the 45 or so Park Owned Homes (POH) I would ensure you have a provision in your addendum to motivate the Seller to provide the titles for them all using an offset. For each title Seller is unable to produce the title company shall reduce purchase price by 5K for each home in consideration for the effort and time it will take Buyer to obtain it. Something like that.
You can wiggle on the price a little for the individual homes if it you feel like you need to make the deal work, but at the end of the day this Park is only making like 60K per year and will require a lot of time and capital to turn it around.