Reservations now posts a sleeper BOS <> WASH every night starting April 5th. This has many possibilities with some speculation.
Expect that this will be a V-1 sleeper to allow for same type off LSL and being able to exchange sleepers. The scheduled 8 PM arrival of the LSL at BOS makes it a problem to turn a sleeper to the night owl. Turns the other way very possible that would leave normal turn sleeper to come from the night owl. The sleeper ending in WASH also allows for a spare V-1 during day for the Cardinal, Crescent, and Silver service.
In the future cut off sleeper(s) from Cardinal, Crescent and Silver trains could be implemented . The only problem for that operation is storage capacity at Ivy city until VRE gets its new storage tracks completed there.
2 other cut off sleepers + night owl would allow for 3 to add another sleeper line to / from one of the above named trains. If this service becomes high traffic maybe a Bag - sleepers could be added NPN <> BOS.
EDIT: Amtrak should have the on board crew actively solicit passenges on the train to buy and occupy unsold space. That will be especially important this first few months to get the word out.