What is the best way to restore an old Multibit wallet to the new version (and also different OS)? My files from Feb 2014 (on a dusty old usb) are as follows, all in a directory called MultiBit. 
directories: 


multibit.log (containing a log file)
multibit-data, containing four backup directories including key-backup, which itself contains two files like multibit-201402xxxxxxxx.key
and five files: checkpoint, info, properties, spvchain, wallet  (all preceded by multibit.) 


It seems the “multibit” prefix changed to “saving” after 0.5.13. Also I have no “wallet words”, only a password, so I guess that changed too.

My thought is to use the import private keys procedure given in Multibit support. This would get around a new Multibit install asking for the wallet keys with the restore wallet procedure. And possibly issues with using a new OS too (Linux).

But:

1) Which multibit-201402xxxxxxxx.key file should I use,  the most recent, or both?  Will this work with my old files; should I change the prefix to “saving”?

2) Should I instead install some early Multibit version and use restore wallet from within the program? In which case can I tell what version I had in 2014 from my log file (or otherwise)?

3) Possibly not relevant, but I’m not sure if my files are from running a Multibit backup, or just manual copying. There is no .exe files in there, but they were created under Win (98 I think).

Note this question Help retrieving my old wallet, is similar, but doesn’t ask about importing private keys, among other things.
Also this question Transferring bitcoins out of an old multibit wallet, has a brief comment by the OP they managed to import their private keys, but not how this was done.

Not massive value in there but I’d be very grateful for advice.
Open a wallet on the block chain.com site and use your private keys there to restore your wallet