Which structure gite and campsite?

My partner and I are looking at buying a property in the southern Corrèze, which includes an old farmhouse to renovate into gites and 5 hectares of land on which we would like to have a small campsite (15 - 20 pitches). After a meeting with the Mayor it was suggested we register with the MSA as Cotisants Solidaires, as this would allow us to develop the campsite on agricultural land. We have been told by the MSA, via the property estate agent, that all we would pay is €300 a year in cotisations and have to carry out some token agriculture for a minimum number of hours a year. Does this fit with your understanding of how the MSA can work?

Secondly, we think that auto-entrepreneur would be the best business model - with 2 gites and a small campsite we don’t anticipate income to reach the €32k limit, at least not in the first couple of years. Do you think this is the right way to go? From reading another post it seems that whichever partner isn’t registered as the auto-entrepreneur can access healthcare by completing the relevant paperwork. We are a couple living together (unmarried).

When would be the best to formerly set up the business? Before the purchase; before any work is done to set up the gites and campsite; or leave it until we are about to start trading? Sorry there are several questions and they are not all about structure but it made sense to give you the whole picture.