With that set up for 5 people, you should have plenty of room. Many of the 1 bedrooms have a second bathroom, so if you get one of those it will be especially good. The only issue is that the pull out sofas are generally terrible. The one we had this year had a mattress that had built in springs! So it was really lumpy and putting it on the floor to eliminate the saggy pull out didn't even help.

You're about 10 minutes from Simpson Bay and 20 from Marigot, unless there's a traffic back up for some odd reason. Via Marigot, it's probably about 30 minutes to Grand Case.