Lots could be discussed on this topic as there is a lot to think about, security is probably the biggest part.

What I see often is employees are given laptops in place of desktops and just connect via a VPN connection and view data as they normally would sat directly on their corporate network.

You could expose the data via a web based portal and use PI Web Parts, again you need to think about how you handle security exposing this data externally. That said, I have seen a few companies that expose KPI's externally based on a secure portal login, where they then use web services to request data that are tightly controlled via PI Trust as to what data can be seen.

You could also use a Citrix thin client and restrict it so they can only use ProcessBook and only connect to your particular PI server.

I would say setting up a VPN is the way to go (as I use it often for clients and it works perfectly). However, it really does depend on how flexible you want it to be and how much data people need and how many people need it. You need to weigh up the cost + effort for each of the methods against the benefit they get (e.g. is it part of their role to monitor the data from home or is it convenient?).

Hope this helps.

VPN is fine if you're running locally intensive applications like Process Book.
But if you want high volume performance from Datalink or the SMT add-in then running Excel on a Citrix box is the best way to go.

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