We used to play the game with 2× base game, ~3 or so expansions (including Inns and Cathedrals), and one mini expansion. The game would take several hours, and everyone would just attempt to build a single giant city with a cathedral to get 3 points per city tile.
Carcassonne is also on Board Game Arena. One of the players needs a premium account, but that's 5€/5$ for one month. Much cheaper than buying a game you might not like.
I like the idea of Carcassonne and have played it many times, but at a certain point I began to enjoy it less than I was annoyed that it never ended very neatly.
I love Carcassonne and play it often but I don't like putting a bunch of expansions in. I have three versions: South Seas, The Castle (a.k.a. Zamek), and Mists over Carcassonne, I play them separately and that way I think they end neatly and satisfyingly. My last game of Zamek with @smorkin came down to the last tile drawn!
I also like the idea of the game, but often the first playing piece lying on the grass determines the winner. Or from then on, it's just a battle to see who can place the most pieces on the grass.
And the cathedral card usually comes at a very wrong time.