You should not capitalize the 'rental' portion of the homes, just the lots. What is the comparable lot rent for this area and type of park?
For this type of park you should break down your valuation as such:
Capitalize lot value: [eg $300/lot rent] 6 x 12 x .5 x $300= $10800 => Then apply cap rate- so if 10 cap then $108,000 for lot portion. Btw: smaller parks tend to be a higher cap rate in general and require a higher expense ratio as you do not have economies of scale as with large parks
Value of 7 homes : No idea so how about $5,000 each = $35,000.
SFR : If this can be parceled out and sold then its easier to attribute a value. If not, then value it like a rental. $600 X 12 X .5 = $3,600. For high level est use same cap rate => $36,000
I know this takes a bit more time but you really need to start looking at parks in this manner. Breakdown the components and valuation of each component. The worst thing you can do is capitalize rental home income above the lot rent.
So using examples valuations above, park, homes, SFR worth $179,000.
Note: My numbers are just examples - the key is how you assemble the numbers.
Hope that helps.