Yes, we could use rooms, but a room in the golden city of God would be far better than any mansion on earth. I think mansion is a good translation.
Revelation 21:
2 And I John saw the holy
city, new Jerusalem, coming down from God out of heaven, prepared as a bride adorned for her husband.
3 And I heard a great voice out of heaven saying, Behold, the tabernacle of God is with men, and he will dwell with them, and they shall be his people, and God himself shall be with them, and be their God.
10 And he carried me away in the spirit to a great and high mountain, and
shewed me that great city, the holy Jerusalem, descending out of heaven from God,
11 Having the glory of God: and her light was like unto a stone most precious, even like a jasper stone, clear as crystal;
12 And had a wall great and high, and had twelve gates, and at the gates twelve angels, and names written thereon, which are the names of the twelve tribes of the children of Israel:
13 On the east three gates; on the north three gates; on the south three gates; and on the west three gates.
14 And the wall of the city had twelve foundations, and in them the names of the twelve apostles of the Lamb.
15 And he that talked with me had a golden reed to measure the city, and the gates thereof, and the wall thereof.
16 And the
city lieth foursquare, and the length is as large as the breadth: and he measured the city with the reed,
twelve thousand furlongs. The
length and the breadth and the height of it are equal.
17 And he measured the wall thereof, an hundred and forty and four cubits, according to the measure of a man, that is, of the angel.
18 And the building of the wall of it was of jasper: and the city was pure gold, like unto clear glass.
19 And the foundations of the wall of the city were garnished with all manner of precious stones.
So the city is fifteen hundred miles long wide and high. The wall all around the city is made of diamond, sapphire, rubies, emerald, etc and stretches over 6000 miles long and is about 230 feet high. The gates of pearl are in the wall, three gates on each side, west, south, east and north.