CAE is a maintenance base for DH (for both the CRJ now, and it was a major maintenance hub for the 328s). I would bet 500BR is just held up there in transit to MYR where they are storing them. If 500BR was there for heavy mx work when we broke off with Delta then it probably would take a back burner to the CRJs now. (just a thought on that)
As for the CRJ, for the past couple of weeks I know that we have been having an extra CRJ overnight in CAE (probably at the general aviation side) because it has been doing NCAA charters... flying basketball teams all over the country. If you see DH planes at stations that we don't currently fly to (BTR, MSP, DEN, etc...) that is more than likely what they are doing.