OK, thanks for clarifying that I can use the PLM as the other leg of the Access Point bridge. The instructions were written assuming you were doing this with two Access Points.
Where the ISY/PLM is located there are at least 2 different circuits, and power from the street goes into the garage first so I have lots of choices for Access Point location there. I'm sure I can find something were they are each on different phases. However, they are far enough apart that I don't believe the RF signal will reach from the ISY/PLM to the garage/Access Point - is that going to be a problem?
I also have a switched relay outlet and dimming switch to install in the house, and they are both dual-band so will they bridge as well?
BTW, I'm starting small because I'm expanding an older LiteTouch system (built my house in 1995 and wired it directly for LiteTouch at the time). My big usages will be several IOLincs so that I have new inputs into the LiteTouch system from Insteon devices (mostly PIRs & remotes), and can take outputs from the LiteTouch system to control new Insteon loads (like a new light that isn't wired into the LT system, and a recirculating pump motor that I don't to run continuously, and doing something with my 6 Honeywell 2-wire thermostats). I don't want to throw away the LIteTouch, but it's impractical to home-run new wiring and I don't think LT has the breath of powerline modules that I can get with ISY/Insteon.