We recently purchased a quad bunk TT and like the layout. It came without any ladders to get up and down from the upper bunks. None are built in either. I know the upper bunk has a 250 lb weight limi...
Our oldest DD is now 5 and wanted the top bunk this year. I made a ladder out of 3/4" dowel and 1"x3" oak baseboard trim pieces I got at the lumber yard. I drilled equal/even holes on each board and glued the dowel into the holes to make the rungs. The hardware store had some brackets that I screwed on the top of the ladder that hook onto the lip on the edge of the bunk. Total cost was a round $32...sorry but I don't have pics.