for leftpawdog - I wasn't exactly following how you wanted to control your sprinklers, but what I've done a few times now is put the 14" elk can (that comes with most packaged systems) out in the garage and extend the databus out there with a single Cat5. In this house, for instance, I have an M1XOVR (output expander) and M1RB (adds 8 more relays to the output expander) and an M1XIN (16 zone inputs) in that 14" box in the garage; that then connects to the garage door and gate inputs; and the outputs hook to the garage doors for control, plus the sprinklers; as well as a couple other auxiliary functions. Added bonus - I could add a keypad out there if I really wanted, or any other bus devices. That location is also right next to my electric panel, so I've considered moving my UPB PIM there for maximum reliability (not that it's been an issue for me).
I set up sprinklers long before we had iPhone apps - used to use my phone to RDP to a computer running ElkRM when I was doing sprinkler troubleshooting/overhaul at the last house - very handy! Was also invaluable the other day when troubleshooting zoning problems on my HVAC - was able to set all the zones as desired from up in the attic while watching the results.