General Cloud Question

I have a client who has repeatedly hinted they want to move all of their storage to the cloud.   However they have approximately 1 TB of data on their current servers spread out over multiple locations.   Some of these files are very large and they use both AutoCAD and Solidworks.

I had suggested just setting up cloud servers and a Remote Desktop Server but they are not interested in that option.  

I have looked around but have not found a solution I feel which will make them happy.   Is there a solution which would allow them to access files from their local computers using Windows Explorer or the standard file menu in their applications.  It would need to be fast enough to not cause problems.   They also want the ability to access these files from anywhere .

The only option I can think of is to setup a cloud server, connect it to the network with a VPN and map drives to it.  However I don't think the performance of this setup would be acceptable and I would have to have the VPN on each laptop instead of the network so it would be transparent to the end user when they are not in the office.

Any suggestions would be appreciated