Basically, the Co-Op parks are just that - independent co-operatives comprised of people who pooled their money and developed a RV park. There's no legal tie to Escapees, Inc. - each park is owned by the independent co-operative - but Joe and Kay Peterson provided expertise during the formation of the co-op and construction of the park. In return, each Co-op's bylaws contains language restriciting membership to Escapees members and allowing travelling Escapees to stay there when space is available.
When you "buy a lot" in a co-op park you aren't really buying real estate. Instead, you're buying a share in the co-op that gives you the right to use a lot on an exclusive basis.
All taxes and other park expenses (common area maintenance, water, trash, sewer) are covered by the co-op. You do pay for the electricity you use. Revenue comes from overnight camping fees and an annual maintenance fee paid by each co-op member.
When a co-op member (a "leaseholder") leaves the park to travel, they have the option of putting their vacant space into the park's rental pool. Travelling Escapees can then rent the space and the revenue is split between the co-op and the leaseholder up to the amount of the annual maintenance fee.
When a member decides to leave the park for good, their membership share is re-purchased by the co-operative at a pre-set amount, then sold to a prospective member. Usually this is the intial membership fee and the depreciated cost of any permanent improvements the member may have made to the space.
Rainbow Parks are owned and operated by Escapees, Inc (a private corporation comprised of Joe and Kay Peterson and Bud and Cathy Carr). Escapees owns the common areas within the park, including a campground for the use of travelling Escapees. The parks were financed by selling individual lots with the park boundaries. Lot owners have all the rights and responsibilities of real estate ownership - they can develop their lots as they wish as allowed by zoning codes, are responsible for their own property taxes, and can sell their property at any time at current market prices.
Park expenses are covered by the revenue generated by the overnight campground. Lot owners are not assessed annual fees.
A few years ago, changes in real estate law made it impractical for Escapees to develop new Rainbow Parks by selling lots within the park. So they developed ERPU - Escapees Rainbow Parks Unlimited. These are long term leased spaces within several of the owned Rainbow Parks.
The lease terms are pretty good - you pay the initial 5 year lease fee, then $1 renews it for another 5 years. When you leave, the full amount is refunded to you - Escapees keeps the interest earned by your money.