Yes and yes.
I have Hoppers called Living Room and Office (My computer room). When I press the DVR button, the top line says DVR:, the My Recordings in red(the current dvr) then in grey the name of the current DVR. Arrow over to that then press Select. In the drop down is the name of the other DVR. Arrow down to that and press Select. You now have access to anything on the other dvr.
From the same top menu, Select the Red My Recordings. arrow down to Timers, then press the Green Button to select Manual Timer.