"Card room" generally means that there is a separate room to play bridge, canasta, etc. Princess has electronic poker tables in the casinos where up to 10 people play with no dealer - all betting payouts, dealing, etc. is done electronically - it really is amazing. There is plenty to do on a cruise - if you want to be active every minute, you can be or if you just want to sit and watch the water go by, you can. Generally a balcony room is more desirable than an inside. If you are concerned about motion sickness, get a cabin midship and on a lower deck. I would rate Princess above Royal Caribbean.
Have a great time!!!