Storing ALL iTunes Songs Locally on iPhone

Hello,

To take advantage of some of the great features of Apple Music I seem to need to switch on iCloud Music Library.

Currently I have all of my iTunes songs loaded locally on my iMac which I sync to my iPhone - meaning all of the songs are stored directly on each device.

Having everything stored locally on both iMac and iPhone is great because I spend a lot of time travelling on the London Underground, UK Long Distance Intercity Trains and Long Haul Flights where there is zero iNet signal on WiFi and Cellular. I also visit lots of places in the UK where the iNet is still painfully slow / not available.

IF I switch to iCloud I understand that all my songs get sucked up from being stored locally on my devices to being stored in the iCloud and therefore are only available for playback if / when I am connected to the iNet.

Not good if travelling.

I understand that once in iCloud I can only download my songs "one-by-one" to my iMac / iPhone to store them locally for use offline.

So - here's my question..

Is there ANY way I can move to iCloud to use some of the neat & cool functions of Apple Music BUT ALSO be able to download all my songs easily in ONE HIT (not individually) so I can use iTunes when away from the iNet.

Better still - is there an option in iTunes to "keep a copy locally" on each device (Mac / iPhone) when switching up to iCloud??

There are lots of users who live / work / travel in areas with little / no iNet access who want to use iCloud Music but are not able to do so without losing access to their full list of tunes / songs when the iNet is not accessible.

I'm assuming Apple haven't thought of this / don't really care???

I'd be grateful if anyone knows an answer!

Bob