I spend about 300 days a year dragging cool cars around the lower 48 in my second home, a custom Kenworth with a sleeper better than your last hotel room (sorry) and 53-foot enclosed van trailer leased to Horseless Carriage. It's often a pain to find a truckstop with access for a laptop and about three years ago I too searched for an alternative.
What works for me is a US Robotics Megahertz XJ5560 w/Xjack pc card modem. I paid $125 bucks for the little gem. Rated at 56k on the receive end, but the normal connect speed is usually 4800bps, often 9600bps, and if I've been a good boy and have eaten all my spinach, a whopping 14400 bps.
While 4800 to 9600 bps seems awfully slow in terms of many of the flash speeds available now, it works quite well for e-mail, both in and out. This is my drill:
As I use AOL, my Nokia 6160 cell phone hooks up with an adapter cord from 3Com, about $79. Last year when I changed to ATT One Rate 1400 minutes plan, I bought a new digital phone. 3com sent me the adapter for the newer type of cell phone.
With AOL, I set up a "Flash Session," allowing me to log onto AOL, wait for the intro, go to "Mail Center" and click on "Flash Session," click on the verify "run Flash Session" and it sucks up all inbound e-mail. I also do outgoing e-mail, stories, etc, off-line and click on "send later." When you log on next time, the screen pops up letting you know there is stuff ready to go out. When you click on "flash session" it will send and collect all e-mail, as well as the copies to sender. Hit the "sign off" icon and after the good-bye, click on "Mail Center" go to the bottom of the panel and slide the cursor to the right on the "Read offline mail" and the panel drops down in the "Incoming/Saved Mail." Click on that little rascal and all of your retrieved e-mail can now be read offline. I usually check/send e mail twice a day and have never gone over my ATT monthly allotment (considering that I talk a lot too...go figure).
For "cruising and surfing" it is fairly slow to load, but doable. I do breeze through RoadStar Online and Truckinginfo.com on occasion with good results. Slow to load, but still good.
Everywhere I have a cell signal it works very well. I have had "Instant Mail" conversations with RoadStar's Bette Garber from a rest area in the bayou of Louisiana and with my wife at the top of Battle Mountain, Nev. Stuck in a whiteout/31-inch snowfall and closed highways in Colorado, I was also able to send and receive e-mail while comfy in my sleeper, enjoying fresh ground cappuccino (Yeah, yeah...life's tough on the road.)
While this may not be perfect for all, it works well for me. And it sure is handy when I waltz into a truckstop expecting to tap into their phone at the table and find it not so. Plug in the cell phone, log on, hit flash, log off and read a dozen e-mails. Total time logged on: 2 minutes.