Bachelorette Ideas in May, in Ontario?

The June Motel in Sauble Beach would be an amazing trip! I gave my bridesmaid that as an option or you can do blue mountain! If you want glamping there's Glen Oro Farm's its gorgeous there!

Following up on my other reply, I see you're in Elora. I am in the Georgian Bay area. I'm not sure what your budget is but there is a beautiful property in the Owen Sound/Annan area called Serenity Cottage, their rates for May 2 day weekends are $2250 total (room for 10 people). Check it out!
https://lakefrontcottage.ca/serenity-luxury-cottage-rental/rates-availability/

This is exactly my dilemma with a June wedding date too! Depending what you want, you could look into renting cabin/lodge/chalet property (maybe off airbnb or vrbo?) That way it still feels like a getaway and the nature vibe of glamling but you've got an indoor retreat and somewhere cozy to sleep inside if the weather is nasty as May can be unpredictable. And since it's still technically "off season" you may be able to find a deal!

What about a spa retreat type of resort? You can go expensive like St Anne's or something more affordable (basically anything other than St Anne's lol).

If you want glamping, there's Footprints resort in Bancroft. It's basically an adult resort that feels like you're camping. You bring food to cook on barbecue grills, a fire pit, and there's paddleboarding on a pond but you get to sleep in a cabin and have a shower. And there's Wi-Fi.