My son (12) and I will be spending the first couple of weeks of August in Poland (Polanica-Zdroj, southwest, very close to the Czech Republic), followed by a few days in London with Ms. p_man. Assuming I manage to cover the basics (adapters, Project Fi, an international driving permit from AAA), any words of wisdom regarding things to do, not do, look out for, be sure to remember, getting some cash before we leave, etc.?

The Poland part is a training camp for him, so other than group day trips to Wroclaw and Prague, there's no time for us to travel on our own. With his equipment and stuff for a dorm room, we'll have more luggage than I'd want to move place to place anyway. It's enough to make a car from LHR look pretty attractive.

I'm have an apartment from Airbnb for most of the stay, so I'll have a washer/dryer and kitchen. Shopping could get interesting - hopefully Google Translate can at least stop me from buying a can of lard based on the pretty pastry on the label.

Seriously, though, the first time you spent a couple of weeks away, what couple of things did you really wish you had, and what did you bring that time and never again?

Thanks!