Photo sync in Lightroom CC and classic

Hello,

I'm afraid, I've been looking around the FAQ and other discussions, but I wasn't able to find an answer to my specific question/problem.

I have been using LR "classic" for years with two catalogues (for travel and home) and I probably have a totel of 45000 images on various hard drives.

Since Adobe introduced the CC apps, I've been using LR on my mobile device (iPhone) for a few snapshots and that is using the Adobe cloud.

I am not thinking about moving more towards the cloud application during my travels, but I don't want to miss out on the classic version of Lightroom.

And since I've got about 35,000 travel photos collected (yes, admitedly a huge number of which I could delete...) I don't want to sync all my old photos (and fill up the cloud).

If been reading and searching about and there seems no other solution than using both apps parallel, unless I want to merge all photos to the cloud. Does this seem feasible to the more advanced users?

Also: Maybe I'm too "old", but I'm still a bit sceptical about the cloud application as I haven't fully understood it. There is one big disadvantage: When travelling, I will often have NO interntconnection for a day or two (or more), so that's why I haven't switched to the mobile cloud version. I understand, that I won't be able to use LR CC if I'm not connected to the internet. Is this correct?

Well, anyone kind enough to help me out with the bunch of question: Thank you very much in advance!!

Kind regards,

Michael