When the DirecTV installer comes, specifically tell him that existing cable cannot be used as it is in use for cable and will remain in use for cable. He will run the necessary coax to the locations you have ordered equipment for, but he will not pre-wire for possible future locations.
I would encourage you to consider a DVR, but that is your own choice. With a DVR, you can also get whole-home service which will allow any DirecTV location to view recordings from the DVR. Given that you do not consider DVR "a must", I see no reason to get the HR34 (the 5 tuner DVR). A regular 2 tuner DVR should serve your purposes, and will be lower initial cost.
I would get all HD receivers to start with. You can feed a SD tv with an HD receiver (but if it is an H25, you will need an adapter cable for it, the installer should be able to provide that).
To move/change a location later, you would need to run a coax cable to the new location. To add a location later, you would order the additional receiver from DirecTV with installation, and the installer would run the necessary coax.
To summarize, order one HD DVR and two HD Receivers. The DVR will be an HR2x series (HR20, 21, 22, 23, or 24). The receiver will be an H2x series (H21, ... H25). You cannot specify a specific model (e.g., HR24 or H25), you will get whatever the installer has on his truck from his warehouse.
I would encourage you to consider a DVR, but that is your own choice. With a DVR, you can also get whole-home service which will allow any DirecTV location to view recordings from the DVR. Given that you do not consider DVR "a must", I see no reason to get the HR34 (the 5 tuner DVR). A regular 2 tuner DVR should serve your purposes, and will be lower initial cost.
I would get all HD receivers to start with. You can feed a SD tv with an HD receiver (but if it is an H25, you will need an adapter cable for it, the installer should be able to provide that).
To move/change a location later, you would need to run a coax cable to the new location. To add a location later, you would order the additional receiver from DirecTV with installation, and the installer would run the necessary coax.
To summarize, order one HD DVR and two HD Receivers. The DVR will be an HR2x series (HR20, 21, 22, 23, or 24). The receiver will be an H2x series (H21, ... H25). You cannot specify a specific model (e.g., HR24 or H25), you will get whatever the installer has on his truck from his warehouse.
