Hi Mark,
I work for Transavia - if your wife's friend hasn't travelled yet advise her to pay attention to the hand baggage/luggage rules - our ground staff are strict! If she wants to bring a regular size roll-aboard/trolley it may get loaded in the belly (free if within size/weight regs) if the flight is full & she boards late.
https://www.transavia.com/en-NL/service/hand-luggage/
In Holland we are thought of as the friendly airline - hope she can confirm this after travelling with us. You do have to pay for food but our sandwiches are better than most lo-co offerings (and at least you have a choice instead of pretzels or a biscuit on KLM Europe) and we recently also started selling a tapas set that seems very popular...
Rotterdam is our smallest base - very easy & quick to navigate as another poster mentioned.
Feel free to PM me if she has any other questions.