The 120v outlets are limited to 100 watts when in gear. 400 watts in park or neutral. Leds solve this.
Yes, remove the Christmas lights.
Or you could buy these...
Amazon.com - 20 Wide Angle Multi 12v LED Light Set; Green Wire - String Lights

So I strung some Christmas lights around my Camelback roof rack and was all excited until I put the car in drive and the rear outlet turned off. Is there a way around this issue?

So is the read window a crack open for the cord?
Wtf, I had no idea this was a thing.
Xmas lights on a vehicle will get you a stunting ticket where I live.
Unless they're red and blue only or blinking... Shouldn't be a problem.