Get a touring bike, a cyclocross bike, or a hybrid, something that can handle 28 or 32 mm wide tires. On a packed limestone path, that should be fine. I have 28s on my fixie and ride it on limestone all the time in relative comfort. I have a rode bike with 25s and it feels noticeably worse.
__________________
I stop for people / whose right of way I honor / but not for no one.
Originally Posted by
bragi 
"However, it's never a good idea to overgeneralize."