For a caravan club, you'll have to supply caravan pitches (and van) only and with the services they require in the caravan club - tents come under a different bracket. You'll also have to have non agri land status on your one acre for you to be able to apply to the caravan club for that land to be registered. Agri land can only be used for agriculture - tents, caravans, yurts etc are not agricultural activities so you will need to know the status of the land first, you will need a change of use if the land is agri (though on one acre its probably not agri land).
Whats the status of your land?
I would love to do ready made and planted hanging baskets/pots. I think it could work on one acre too, its just the getting orders bit thats the hard bit, growing and putting effort into growing them is the (so called) easy part. Many shops, outlets, hotels, garages, pubs buy in their plants and decorations. Get into that chain and you may be able to make a living in potting and growing flowers and other plants. That could be fun.
I think I could plant flowers all day, that sounds a nice job to get into. - the hard bit is making people aware of your worth and quality and them getting them to buy from you because they understand that fact.
Ta
Baz