I haven't done it, but I do have a lodge on a holiday park, and would advise the following:
Get a solicitor who knows about the sector (these are rare). There are numerous pitfalls that you could fall into, so don't sign anything until you are certain that you understand the implications.
Don't assume that the rent covers council tax responsibility. If you are not paying CT in your own name, you are probably on a holiday park, which is a whole different ballgame - do not even consider living on one, as it is illegal to do so, and you risk eviction with short notice if you try.
Check the actual resale figures for units on the park you are considering. Don't take the word of a salesman - ask to see real examples and ask to speak to residents who have bought and sold.
Ensure that your contract covers what happens if you are asked to move your pitch. You could, say, have a sea view when buying, but find yourself next to the bins a couple of years later unless there is a clause that protects you from this.
Check with the solicitor that if the park changes ownership you will maintain the contract you sign when you buy. Remember that you will own your unit, but not the land it sits on, which massively reduces your rights. Some rights will be included in your contract (can you keep pets? do you have a private garden? outside storage rules? can grandchildren stay over?) but you need to be sure that these can't be rescinded if the park changes hands.
Get a copy of the main legislation that covers park homes. They are different from holiday parks - owners on park homes have more rights - but you need to be clear about things like ground rent increases, and who is responsible for what. Water rates, gas charges, site facilities such as shops or laundries, street lighting - who determines the prices of these and who pays for maintenance?
That's all I can think of for now, but it all boils down to 'proceed with caution', I'm afraid.