Andersen boutique or Ac Bella Marriott

Andersen Boutique hotel is far from the Metro, which you will use to get to the Bella Center. AC Bella Sky Marriott is within walking distance from the Bella Center and close to the Metro station.

I suggest you stay at the Bella Sky and take the metro in the evening.

Personally I have never stayed in the Andersen hotel, but once in Bella Sky - and enjoyed it very much. If you can get a room high up the view is fantastic. Our room was on the 21st floor and had floor to ceiling windows. Very challenging for my altitude anxiety but very good for the view.

I second staying at the Bella Marriott, for easy access to the conference. The metro can take you into the city centre in the afternoon and it runs all night, so you can return whenever you feel like it. And as said the Andersen is near the central station, but It us not near the metro you need to get to the Bella Center.

Thanks l.p.enersen and Morten for helping me makeup my mind! One more question, which parts of the city would be nice to sightsee, visit or eat at? I'm looking for different places to go to every evening after the conference (4 pm onwards).

You’re welcome. Most of the main sights are concentrated in the city centre in the old medieval part of the city. You can take the metro to either Nørreport or Kgs. Nytorv. By Kgs. Nytorv you have the famous Nyhavn canal, lined with colorfull houses and bars and restaurants, though the drinks are a bit pricey. You can also take the metro to Christianshavn and explore that neighbourhood, it was modelled after Amsterdam with canals and narrow houses.

It depends on the time of year. Assuming it is in the summer half of the year I suggest:
Take the Metro to Kongens Nytorv (Kgs. Nytorv; Kings New Square) and

1. Walk down Strøget (Pedestrian street), cross Town Hall square, and visit Tivoli.
2. Go to Amalienborg (where the Queen lives), then Nyhavn (New Harbor) and have a drink (beer, cola, wine, coffee) at an outdoor restaurant, eat in an indoor restaurant (temperature dependent)
3. Go to Rosenborg, where they keep the Crown Juwels - it won't be open (unless you are in the high tourist season), but the garden is nice.
4. Go to Nyhavn, cross the harbor and visit Christiania

Any more days? I'm out of ideas of things you can do in the few hours you have each day.

Thanks again! These will fill up my summer evenings in Copenhagen! As of now, I'll have one full day free. What would be must see/do on that day?

On a full day you could visit Roskilde (https://www.vikingeskibsmuseet.dk/en/, http://www.roskildedomkirke.dk/english/) or Helsingør ("Elsinore") (http://mfs.dk/en/, http://kongeligeslotte.dk/en/palaces-and-gardens/kronborg-castle.html). Both are easy train travels. Use https://www.rejseplanen.dk/webapp/index.html?language=en_EN to plan your journey.