The question "Why do Han et al. go to Maz’s castle on Takodana?" has a good answer about ditching the Millennium Falcon because they know the First Order is looking for it in association with BB-8, Rey, and Finn.
But given that BB-8’s orange and white color scheme is described as unusual for a BB-unit by Poe Dameron, why don’t they paint him or something?
He’s a BB unit. One of a kind. Orange and white. Utterly unique and utterly invaluable.