MES in API Zone 1 Environment

I am looking for some advice on implementing MES in a ZONE 1 API Plant. We need a station that can be used to record data electronically into the Electronic Batch Record (EBR). The problem is that there is either no PC in some of the rooms, or there is a Challenger unit that is running another system (e.g. a proprietary DCS).

Is it acceptable for the operator to walk from Room A, where they obtained the RAW data and enter it into the MES? Would it be acceptable if a witness signature would also be required?
Do we need to install another challenger unit;
Is there a mobile device that could be used that is both compliant with Zone 1 API requirements such that the operator can enter the RAW data into EBR in the rooms that don’t have computers?

Another option I considered was sharing the challenger between the existing system and the MES - whether this is via a KVM switch or a remote desktop connection from the DCS to the MES.
Would a laptop be an option and do you know of any laptops (or tablets) that would be suitable for legal use in an API Zone 1 area?
Any advice would be great. I hope I have come up with some reasonable options, but I am not experienced in ZONE 1 API areas.

All help / advice / input will be greatly appreciated.