Thank you all for the responses. I don't know specifically what's wrong with the engine yet. All the Chevy dealer could tell me was it was "blown". They didn't have lift or capabilities to look into it any further - their garage isn't set up for motorhome work. Yesterday it was towed 5 miles up the road ($416!) to a mom & pop truck repair location.
I have more confidence in them than the dealer, and as many of you suggested, I did NOT like the idea of dealer markup prices. I only went there because there was oil and smoke pouring out of the engine when I got off the highway in an unfamiliar area on a Saturday afternoon. My choices were limited and I had to keep to a schedule. Preliminary google searches didn't turn up too much, but I had to find a place to park it.