I installed a power inverter in the RV to power mom's laptop. It is permanently mounted in main cabinet, upside down under the new shelf. Because this cabinet was originally build as a media cabinet, it has two 12V DC cigarette lighter ports in the back to power the original TV and VCR. So I was able to plug this inverter to that 12V power source.
I did a lot of research on inverters. And I also asked some friends who have a lot of experience using inverters. The conclusion was clear. Do not buy an off-the-shelf inverter from Radio Shack, or any other consumer electronics store. Everyone I spoke too ended up with an AIMS Power inverter, and they have all been very happy with them.
AIMS Power is based out of Reno, Nevada. You can't buy directly from them. They recommend that I buy my inverter through their web retail channel The Inverter Store. I ended up buying their 400 Watt stand alone model. It was only $34, and with shipping $41.
This inverter doesn't come with mounting points. Since I was going to hang it upside down on a moving vehicle, double sided tape wasn't going to be good enough. So I ended up drilling 4 small screw holes into those lovely aluminum side fins and mounting it with screws through the top of the new shelf.
It is pretty quiet, and seems very well built. I ran some tests and and it powers Mom's Macbook Pro just fine. It also doesn't draw too much power off the house battery.
We will see how this works out. So far, so good!