I carry one of these with 3 batteries when I wheel: [url="http://www.amazon.com/Black-Decker-LCS120-Lithium-Ion-Cordless/dp/B004JMZH1W/ref=sr_1_2?ie=UTF8&qid=1354412148&sr=8-2&keywords=black+and+decker+battery+chainsaw"]
Never tried this, and I've never been a big fan of Black and Decker's Black and Decker branded tools -- although some of them are okay for casual use. (Their DeWalt line is pretty good usually.) However, this looks like it might be the solution to the OP's concern, if his concern is branches in the road. It would take a very hefty inverter and a ton of extension cord to operate the 120v saw he described. This battery operated would take a lot less space (no extension cord) and weight and it would cut (at least theoretically) most of what a person would likely care to cut and move out of the way. For real bushwacking or clearing a fallen 20"+ tree out of the road, this won't come close, so a lot depends what you imagine wanting to do.
Even this little battery operated saw needs about as much maintenance as a gas saw though. You don't have to carry fuel, but you still have to keep the chain sharp (and a short chain like this is going to get dull fast), and you have to carry bar oil. It isn't any fun to cut wood when a chain is dull. So in terms of maintenance, you're trading charging batteries for mixing and carrying fuel. There's a safety advantage to not sloshing gasoline around in the back of your rig, but there's not really much less maintenance. The corded saw might have more power and run longer than the battery powered saw, but it would be a much bigger hassle, in my opinion. It would still need bar oil and the chain would need frequent sharpening.
For me, since I already have an 18" Husqvarna 346, if I were dealing with this kind of wheeling, I'd secure the saw I already have in the back of my FJ, with a full tank and little or no extra fuel and I'd know I could move just about any tree out of the way.
All of this doesn't touch the safety issues involved in cutting standing or fallen timber. No matter what tools you use, this is not something a novice ought to be doing.