As per submarine d you’re not going to get anything light / cheap that will hold off a determined bike thief. Centre spaces are rife with bike theft – I’ve always kept my bike in the actual lodge when we’ve stayed there.
The only lock that’s vaguely portable and half decent is a hip lock – I’ve got the top one that cost about £60 in a sale and is sold secure gold. Even still – when locking with it I make sure it’s as high above the ground as possible and as tightly wrapped around the frame as I can. You want it out of range of big bolt croppers – then the only thing they’re going to get it off with is a battery powered angle grinder. Nothing is going to guard against that really.
The alternative is a beefy d lock – but that’s less portable. Kryptonite New York Lock I’m the short shackle size has been the one I’ve always gone for. Again, Keep it away from the floor and big bolt croppers – but an angle grinder will probably do for it too.