Situations like you describe are cases where I'll just find a bike to rent, rather than deal with a substandard folding mtb.
IMO, folders do better for urban types, and for non-mtb purposes. Like commuting. You need it to fold because you do a multimodal commute and space is limited. Or storage space at work or in your apartment is limited.
If I'm traveling with bikes, then I work out a plan for security as part of my travel plans. If I'm traveling and didn't bring a bike, but find a place I'd like to ride while I'm out, that's when I look for rentals. If no rental, then no ride.
I still don't consider leaving a bike inside the car to be a very big upgrade in security. Cars, vans, and trucks get broken into regularly whether there's anything inside or not. Plus, leaving stuff in there all the time is going to be hard on it. Helmet wouldn't last long stored inside a car in the southern portion of the country. I've had a helmet start melting from being left in a hot car for a few hours.
IMO, folders do better for urban types, and for non-mtb purposes. Like commuting. You need it to fold because you do a multimodal commute and space is limited. Or storage space at work or in your apartment is limited.
If I'm traveling with bikes, then I work out a plan for security as part of my travel plans. If I'm traveling and didn't bring a bike, but find a place I'd like to ride while I'm out, that's when I look for rentals. If no rental, then no ride.
I still don't consider leaving a bike inside the car to be a very big upgrade in security. Cars, vans, and trucks get broken into regularly whether there's anything inside or not. Plus, leaving stuff in there all the time is going to be hard on it. Helmet wouldn't last long stored inside a car in the southern portion of the country. I've had a helmet start melting from being left in a hot car for a few hours.