The past two fall seasons we have done long trips in the rockies. Last year 5200 miles, this year 7600 miles. All was done within our normal monthly budget including scheduled vehicle mx. We do alot of boondocking and eat in the rv, not in restaurants.
We have found since we are not at home, those costs drop dramatically, enough to cover our travel costs. This past trip we got 19MPG (diesel) cost per mile was .21 for 7600 miles, average camping cost per night for 6 weeks was $10. It is all in how and where you camp.