Motion sensor security lights outside, and a cheap wireless security system is also a good choice.

It's most likely a wireless router, so it doesn't matter where the router is placed as long as its within close proximity (50'-100') of her devices.

Most wireless thermostats and control devices use protocols such as Zigbee or zWave for communication and not 802.11 (WiFi) which is a power pig.  

you need to investigate, because the rules for a 4 unit (considered residential) and the 5 unit (considered commercial) in many jurisdictions in WI you must have a sprinkler system in the 5 unit, some places require it in 3 or more units, as well as hard wired interconnected smoke and CO detectors, you may be able to get away with the wireless inter connected units, but check with the local fire inspector. 

But I also know that wireless signal can degrade causing poor picture resolution.I personally like all of the points especially numbers 2, 4 and 5.I can't see an issue with running security cameras in common areas, parking lots or corridors.

It was written in a variety of languages and worked on a variety of devices from wired PCs to wireless bar code and RFID scanners.

They don't require a landline, and have flexible add-on features.Looks like Ooma has a wireless adapter, but not for their business service product (according to their website).Good luck!

(This is a hysterical laugh...)Here is what I've been searching for the last half hour:IP Security Camera with or without tilt controlNight visionMotion sensorBattery operated/solar poweredOutdoor/indoorBuilt-in internet / mobile connection (ie records video to cloud without internet present)Affordable (<~$100)I'm not sure if I'm searching the right keywords, but here are the items I've found which still don't do fall 100% under the criteria I listed above:http://www.amazon.com/TENVIS-JPT3815W-Surveillance...http://pro-vigil.com/live-security-monitoring/http://www.amazon.com/Foscam-FI8918W-Wireless-Netw...http://www.amazon.com/Covert-Special-Ops-Cellular-...The last one is a trail cam which takes pics and sends them through MMS!

.$10 - http://www.homedepot.com/p/Defiant-Wireless-Home-S...

This is great, as Internet may be spotty (outages or poor wireless), or your modem may occasionally hang, or perhaps guests disconnect it for some reason.