There are a few people on the forum doing something similar.
It can be as expensive or cheap as you make it, and as good or bad as you make it.
We're approaching our six month mark in a 24 ft Class C (two adults, baby, and two dogs). We alternate between RV, hotels, short/medium term rentals, as makes sense for the location we are in. When camping we alternate between state/national parks, free campsites, and various boondocking spots, few RV parks thrown in.
Boondocking is free and nice. State parks tend to run $20 - $40 / night it seems. Expensive campgrounds closer to the city we've paid ~$50 / night.
$50 / night is about my cut-off, since that roughly equates to $1500/month rent. Above that point, I'd find an alternative :)
Driving around too much makes you burn gas, so it makes sense to economize. Drive short distance, stay for a while. Enjoy yourself :)
I had broken down and written up our experience and expenses comparing our costs driving cross country in an RV vs a car
That's only one set of experiences and expenses, but maybe you can use that as a baseline for how things compare. Hope that helps some.