Tejano: If you use dry ice do not put it directly on the meat or it freezer burns.
Ended up using blue ice cold packs. These kept things frozen for about four days in cool weather. The dry ice was kept in an insulated mylar bubble wrap bag with paper or plastic between it and the meat. These only lasted about two days and the meat that only had the plastic between it and the dry ice I trimmed away. Decided it is only worth it for transporting previously frozen meat.
Yes to combining transport and ageing so it is usually a combination of methods for me. Mine is like Tedhorn's but I start draining the second day and thereafter unless I am intentionally brining the meat.
