You didn't say how/where they'd be entering info. If when back at the office they will enter data from paper sheets or a logbook that they use on the road, then Excel presents a problem in that it doesn't support simultaneous users but Access will. I agree with Access having a somewhat steep learning curve, especially if you want to do it right and avoid common pitfalls. More so if you get involved in VBA code. However, there's lots of help available on-line. If you are not familiar with db normalization, you must start with that.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.