Gary,
Our old '83 Chevy Class C TranStar Champion (1-ton G30 van chassis with a stock 350 with a Quadrajet, TH400, Dana 70) was used for the past 10 years as our motocross racing tow vehicle. We, my family of 4 to 5, used it almost every weekend from March through November to pull our heavy trailer, but the trips were within a 250 mile radius for the most part. The places we went were not designed with motorhomes in mind, but she was 100% reliable.
We were all going to go on an extended vacation in my uncle's huge Winnebago a few weeks ago. But the reality of our initial plan to have so many people (seven) in that one huge RV for 2 weeks was too much, I decided. So I frantically got our old Chevy ready at the last minute.
I was very worried about everything since it saw no use last summer when we stopped racing due to fuel costs and other interests. It has sat a long time and nothing is worse for a vehicle. I wanted to replace shocks, brakes, steering linkage, wheel bearings, u-joints, etc. and just generally spend all of our vacation money and worry myself to death before we even left.
I could not find anything wrong with any of those parts except the idler arm and time was too short. So I tuned her up, replaced the idler, loaded her past all reasonable needs, and hit the road.
We did 2 weeks of mountains followed by mountainous high desert followed by more mountains; and I'm talking some VERY hard, hours-long, 8 to 10% grades. I even had a big steel motorcycle carrier on the back with my DR650 'zuki in it just to make sure it was completely overloaded.
3600 miles in all, and now the old girl has 97K on her. Not one problem other than a gummed up Generac generator carb, which I disassembled and cleaned while camped, and then it was perfect, too. We really put her to the test on that trip!
Iowa, Nebraska, Wyoming, the Medicine Bow Mountains 12k peak, very steep and a good excuse for my 15 year old to ride the motorcycle up over the mountain peak where we played in the snow. Then more Wyoming, then Utah with the big grades around Salt lake City, across Nevada to the desert for several days of prospecting for gold.
Back across Nevada, then up through Idaho and across to the Snake River Valley in Wyoming which we followed up to Jackson Hole, then did Yellowstone for a day. Exit east out of the park and on to Cody, WY then up over the huge Bighorn Mountains (heckuva pull; be ready for some really extended steep grades that will take all day). Onward to Devil's Tower, Deadwood for a day, and then Rushmore; all in the Black Hills. A long night across South Dakota and the Badlands and into Minnesota then back to Iowa.
Your trip sounds like it will be even longer, but the other guys are right. If you have some time before you leave, just put some miles on her and see how things are. Our's has never had ujoints, or any motor or transmission work. I have always run synthetics because our camper has never had an easy life. Those old Chevy's are tough!
Nice thing about them is the ease with which you can find parts and fix almost anything yourself almost anywhere if you have to.
When I first got ours, 10 years and 40k miles ago, I went through and changed out the water, fuel, and oil pumps, hoses, belts, oils, etc. Put a new alternator on a few years later along with premium front brake pads. Also built a massively stout frame extension, added air suspension, a 50 gallon gas tank, a 5500watt Generac, built a motorcycle carrier/receiver hitch assembly, etc. New radials replaced the old bias tires a few years back (what a huge difference in ride!). Now a new idler arm because the passenger front tire was exhibiting some abnormal wear patterns.
I have never done the rear brakes. I checked them before leaving and found them fine. They held that overloaded camper by themselves (shifter in neutral) using just the parking brake on a 10% downhill grade when I tested them on the trip. GOOD parking brake!
The ONLY thing that has ever quit on me on that Champion is the fridge just recently and the alternator years ago just 4 miles from home. The cruise control, dash air, roof air, water system, etc. etc all work perfectly after 97,000 miles and 26 years.
We installed an a/c fridge for this trip along with a 1500 watt inverter after the parts supplier sent the wrong cooling unit to fix my lp/ac/dc fridge. I'll probably go ahead and fix the old fridge even though I'm putting the old girl up for sale to buy a big pickup camper.
BTW: If you are a flatlander like me, but not a truck driver like me, you may wonder what an 8% or 10% grade is.
10% means that for every 100 feet you travel, you are climbing (or descending) 10 feet vertically. 8% is 8 feet vertically. Now, 100 feet is not very far, only 33 and 1/3 yards, or three first downs. To climb 10 feet in that distance is VERY steep. You would not want to walk it very long.
You mountain hillbillies can go ahead and laugh at us flatlanders, but between those grades, the accompanying sharp curves, and the thin air; we flatlanders will have a new-found respect for Western vehicles and inhabitants!
Attention: TDR Forum Junkies 
