Are you willing/able to make the repairs yourself? If you have to hire someone to do all the work, it probably doesn’t make sense. I know from the emails I get it is often hard to find someone to repair a mobile home. Regular plumbers don’t like them because they use different parts and are not the same as site built homes. I have no idea what labor rates are in your area, but at $100/hour it would not take long for the repair to match or exceed your cost for the home.
I asked some guys I know who specialize in buying HUD repo’s how they handle the plumbing question. (For those of you who don’t know, these homes are purchased without any of the utilities turned on and may have frozen at some point.) They said it isn’t usually that big of deal. The pipes tend to freeze at a low point and drain from that break. So they turn the water back on VERY carefully while having someone under the house listening for leaks. They have never had to actually replace all the plumbing.
Amazon sells fittings that are expensive, but very easy to use and fool-proof for amateur use. So you may find you can get all the pipes fixed for $100 or so of parts plus your time.
Could you work with the owner to check out the pipes before you actually buy it? Perhaps connect a garden hose from a nearby house with the understanding you can try to make the repairs and back out of the deal if you can’t get the pipes fixed.