If you don't already have a laptop computer for travel or if you struggle trying to get things done on your small smart phone screen when you are out of the office, here is a cheap alternative - the $120 refurbished Acer C720 Chromebook.
Chromebooks are probably the most secure portable device a mobile lawyer can carry. This is particularly true if you enable second-factor authentication on your GOogle account. And despite not running a full desktop-style operating system, they can do nearly everything you need to do while on the road. You can even use the very nice Cloud-based versions of Microsoft Word, Excel, or PowerPoint and access all of your documents and files stored on OneDrive (not to mention Dropbox and Google's own Drive).
You won't mistake the Asus C720 for a Macbook Air or ThinkPad X1 Carbon. It is a bit thicker and more plasticy. But running the lightweight Chrome OS, it is surprisingly speedy. This blog post was written on my own C720.
The refurbished deal comes directly from Acer's Ebay store. It is always best to buy refurbished products directly from the manufacturer. They have the highest standards to assure that the refurbished item works and looks like new. I've purchased two refurbished C720's from Acer (my wife uses the other one) and both have been perfect.