Re: He should have just emailed it to himself encypted of course
Data caps in the western world are not an issue. Most of us have ASDL or fibre. Plus a monthly unlimited 4G phone with data contract phone is about 30 pounds in the UK and 16 euros in France. There are also data sims for one off needs. For the less well served there is Starbucks and MacDo. You are likely to find such a hotspot in the Airport at each end of your trip.
If you are going to a place without internet "all that you can eat", they are probably not going to give a hard time at the airport to open you PC, except perhaps North Korean.