I use a Cradlepoint MBR95 wireless router with a Verizon aircard/modem connected to it. There are other wireless routers out there - WiFi Ranger for one.
We have two laptops and a wireless printer connected in a network all the time and once in a while a guest. The MBR95 has a "Guest' feature that will allow a guest to connect with their own password and access the Internet but not have access to our network.The MBR95 will handle up to ten wireless devices as I recall. Besides the printer and two laptops we have four Kindle devices and our TV connected to the internet through it.
You were going to stop by our site at the Coldbrook campground once when we were there in the summer but it didn't work out. Hope you can stop by our house in CO. We are off the road and settled down now.