djb_rh:
It wasn't a huge LED, but it was a fairly high output white one. I saw that it claimed internal pull-up resistors, so I didn't think I needed one. Plus the circuit in the Series1 tutorial didn't use one. Ugh. There was a time when I would have never considered not using one, but I've seen more and more examples of not needing them lately that I got sucked in.
Size doesn't matter 
much, even a small LED will draw a lot of current given the chance, the V/I curve is pretty much exponential. Lots of bad practices out there, some in books even.
I can't do anything more than ask the gate to open via the relay, but still like the idea of the heartbeat. I guess I can use a mini arduino on the sending side to keep things small.
Or just set the XBee up to transmit once a second or something. No MCU needed then.
Anyway, great insight. Thanks. My life would have been a lot easier if I had never seen those series 1 tutorials, but I think you got me straight. Again, many thanks.
You bet. Good luck again, hope your XBees are OK. I'd start by reloading firmware then checking them out. Great little devices.