I had been running a portable battery operated LED light up until last week, then I bought a couple different style LED lights to mount inside the van.
I bought a strip type unit with an adhesive strip on the back, another type is considered to be an automotive interior dome light, and finally I got a long strip unit on a swivel, which allows me to to create a subdued light effect when tilted up against the ceiling.
Here's a few pics of the various lighting in use.
The round one is the portable battery operated unit .
This is of the dome light style unit which has 9 leds per fixture, with just one running, and with both on.
And finally the long bar swivel unit in it's outward shining position, and then in subdued mode:
I found so many different options when it came to the cut type strips, and an equal amount in dome light type configurations.
But if you only want to read, a little portable battery powered unit worked fine for me.