You'd still have to climb inside the base cabinet to do either. Jmooney's right. Pick up a basin wrench at Home Depot. There are several styles available at price ranges from about $12 - $35. Yes, that's a lot of money to pay for a tool you may only use a few times in your life, but it makes the job soooooooooo much easier . . . and you'll actually have skin left on your knuckles when you get done.
Of course, if you're going to replace the sink also, then it's easier to put the new faucet and water lines on the new sink, then drop everything into the sink hole.
RV manufacturers use cheap faucets, and, because our water comes from a variety of sources (sometimes of suspect quality), they tend to not last very long. Virtually any kitchen faucet will work in your RV - provided it uses the same number of holes as the old one. I'd suggest purchasing a reasonably priced, "name brand" faucet, rather than the cheapest one you can find. It will perform better and last much longer, so you won't have to do it all over again in a year or two.
2013 Eagle 266RKS
2011 Ford F-150 w/3.5L Ecoboost & H.D. Tow Package