If color is a requirement, then laser is out, since color laser printers are large and pricey. (And the smallest ones aren't particularly well built.) Also, I'd be suspicious of a laser printer for use in an RV, since they can draw a lot of current when they start up.

That pretty much leaves you in inkjet-land. My advice is not to fall for the cheap intro prices, and instead price out the cost of a printer plus its first ink refill.