Hardware best practices for data entry while doing field work

I have a client who sends medical professionals out into the field to perform checkups and other simple procedures in low income areas for free. They are currently doing their work in an entirely paper based way but want to move everything over to digital / paperless.

The challenge is to come up with a way to facilitate form-based data entry (i.e first name, last name, address, etc) for someone who may be standing up at a strangers front-door interviewing them. In a scenario like this a laptop is potentially not viable, but a tablet or smartphone may be cumbersome and def. slow in getting the data entered. The forms are rather long and some inputs may require a significant amount of typing.

I'm curious if anyone has ever come across this type of scenario and has any insight or, even better, research or articles on options and/or best practices to handle this.

Thanks in advance, Michael