Deep breaths, deep breaths! :) If you can't afford it, and she can't either, just keep kindly explaining, like a broken record, "I hear you, mom, but we don't have the money to fund any more things, and so unless feel that you would like to pay for this, I'm afraid there is no way this will be able to happen." Lather, rinse, repeat as necessary.
Methinks your mom is overdoing it - I agree with you, not every second of the time needs to be planned. And furthermore, what about the rehearsal dinner (which, BTW, is typically paid for by the groom's family)? What's this with the wine tasting? People need to have the time to relax and socialize and enjoy the beach, or read a book by the pool, they are not 5-year olds, and they do not need or maybe even do not WANT someone to schedule their every minute; I'm with you. Your mom is just getting hyper-nervous, and is over-thinking. If you have some sort of commercially-prepared wedding checklist - or if you can FIND one that suits your needs - you can point out gently that it does not list these things, and therefore such activities are not traditional and certainly not required. (I mean, come on - planning for the night AFTER??!! You, and they, may not even be there! Get real!!!!)
When she pulls this stunt, you can say you appreciate her thoughtfulness (yeah, I know, bite your tongue!!!), but it is important to keep the budget in mind, and you are sure that your guests will enjoy themselves. Say this kindly, and without a trace of frustration in your voice, even if you feel like you've said it fifteen times, and you'd like to choke her.
Look at it this way, sweetie - it's good practice for being a parent, when you have a 4-year old that is diligently and constantly thinking up new ways to create mayhem and destruction! LOL. It is a wonderful skill to learn the art of deflection, which I know is REALLY challenging for straightfoward, say-it-like-it-is kinds of people like you and me!!! Good luck, and hang in there!
Oh, and remember that every hotel in the world has tourist information and flyers in the lobby. Part of the fun in traveling is the special activities you can find through your own hotel.
PS. Given your comment about your fiance's lack of help in the planning, then maybe you can use that information, if you choose to, in talking with your mom. "I am just out of time and energy, as well as money, to be planning any more than is already on our plates. I know you mean to be thoughtful, mom, but really, you are just stressing me out with these add-ons, and I really please wish you would stop. "