This is not going to be very helpful sorry but for me it completely depends on if it's something I want to go on! I always roll my eyes on here when people are aghast at the very idea of spending time! with their friends! paying! for fun! (as pps have proved).
To me, if it's with people I like, the hen do is just the 'reason' for the trip, but it's just a trip away with mates, which I like going on. Like any trip you have to pay for food and accomodation so as long as it's not extortionate I wouldn't begrudge any reasonable amount.
If it's someone I don't know/like as much so don't want to go and don't feel obliged (and literally the only person I would feel I'd have to say yes to is my sibling), then I'd just say no thanks can't make it and spend nothing!
Basically I would make sure the basic costs are as low as reasonably possible (travel, accommodation etc), then make everything else optional, so people can choose what they want to do rather than being forced into yet another sodding cocktail making experience!
e.g. fri afternoon: cheap pizzas or takeaway, drinks in the accomodation.
sat morning: go ape adventure for those that fancy it, chilled walk around the park for those that don't
sat evening: cocktail making experience for those that want to, sit in the bar with a drink for an hour for those that don't. Meal out (perhaps a set menu so no stress about splitting the bill). Onto a bar for those that want to, back to accom for others.
sun morning: spa for those that want to, mooch around shops or early departure for others.