Oh yes, she did stay at Gavnø for a period.
As for her work at Microsoft in Copenhagen. It was some sort on consultant job I believe. I.e. no fixed hours.
If I'm to be honest I doubt she put in that many hours at Microsoft. The period where she lived in DK up to the engagement was IMO, so that M&F could get to know each other on a day to day basis and see if they could live together for an extended period.
And just as importantly for Mary to get to know Denmark, the climate, the people, the scenery, the culture and learning to live in a palace with protocol, security and servants. It's quite a transition actually!
We can all dream about suddenly living in a palace, but it's also a quite overwhelming culture shock to actually live there for real!
What's the proper way to address the servants and staff?
How do I get used to having them around? And when do I use them? And for what?
How do I get things done discreetly? - You don't just pop down to the chemist for sanitary products, for example.
You can't just walk butt naked from the bathroom, because you forgot your bathrobe, lest you bump into someone.
You can't shuffle down the stairs in an messy kimono, slippers and morning hair, because you forgot something in the car last night. You may walk into Frederik's adjutant.
There may always be someone within earshot, even though they are discreet and have signed a pledge of confidentiality. You can't just call to Frederik down the corridor: I could lick your back, you yummy you! or Frederik, I could wring your neck!
What fork do I use in this here culture and family?
What's the procedure if I want to invite a couple of girlfriends over for coffee?
What do I do if I suddenly bump into the Queen or another member of the DRF? (That sort of happened. I.e. an unprepared meeting with QMII.)
Getting used to a PET officer suddenly knocking on the door saying an alarm has gone off but everything is under control...
Outside the palace you are never 100 % private. There is always the chance that someone will recognize you and you may be photographed any moment.
So no picking your nose/ear in your car, while waiting for red light.
All the multitude of little things you have to learn and get used to. - Something another woman who married into another royal family, perhaps never had time to get to learn and adjust to, before it got real.
Eh, not necessarily. The affluent are just the loudest, most visible ones 
