I just wanted to add my experiences. About a year ago I got a Verizon USB mifi stick. I considered the 5 user model but was convinced by a few people that a
Cradlepoint router was the way to go. It has much better range and can support 16 users instead of 5. It works on either battery or AC power and gives you all the features of a full-size router. Just plug the USB stick into it and you've got full powered wireless internet.
The Verizon stick with the Cradlepoint router works great at the lake. We used it on vacation last year (near the Weirs) and all our laptops and iPhones had great service. We've used it on trains and in our car and it has always worked great.
Of course things change very quickly and I've recently found another solution. I jailbroke my iPhone 3Gs and installed MyWi. Now I can use my iPhone as a wireless router. I can also plug the iPhone into my computer and use it without wifi or connect to my laptop through bluetooth. MiWi does it all. I'll keep using our Cradlepoint router with the Verizon stick for now but MiWi gives me some other good options.